Press Release

PalmSource Adds AT&T Wireless to the Palm Powered Mobile World Program

SUNNYVALE, Calif., June 29, 2004 — PalmSource, Inc., (NASDAQ: PSRC) provider of Palm OS™, a leading operating system powering next generation mobile devices and smartphones, today announced that AT&T Wireless has joined the Palm Powered™ Mobile World program, connecting mobile operators, application developers and users of Palm Powered smart mobile devices in the Palm Powered Economy. AT&T Wireless joins existing mobile operator partners Orange, Sprint and Telefﾃｳnica Mﾃｳviles Espaﾃｱa, as well as more than a dozen other infrastructure and middleware partners, in this program that capitalizes on the growing smart mobile device market.

As a partner in the Palm Powered Mobile World program, AT&T Wireless will collaborate with PalmSource in several areas, including:

• Leveraging the Palm OS developer community for the development of Palm OS applications optimized for the AT&T Wireless network;
• Joint-marketing efforts to identify key Palm OS vertical applications based on AT&T Wireless' target markets and supporting the distribution of these solutions to AT&T Wireless customers; and
• Collaborating to align the Palm OS platform roadmap with AT&T Wireless' device and network requirements, facilitating cutting-edge Palm Powered smartphones to be brought to market.
  

As a result of this collaboration, AT&T Wireless subscribers can benefit from easy access to a variety of applications for their Palm Powered devices, while Palm OS application developers can gain from the addition of a large customer base served by the wireless carrier. In addition, AT&T Wireless can provide direction to Palm OS developers on desired vertical applications that take advantage of the AT&T Wireless network, technical and business requirements.

The combination of the industry-leading Palm OS platform together with the capabilities of AT&T Wireless data services is expected to promote increased development of Palm OS applications optimized for the operator's GSM, GPRS and Enhanced Data Rates for Global Evolution (EDGE) networks. It is anticipated that new, innovative applications will take advantage of the advanced network and Palm OS platform stimulating revenue growth for both mobile operators and application developers.

"The partnership with AT&T Wireless illustrates our commitment in collaborating with leading mobile operators to accelerate growth of the Palm Powered Economy," said David Limp, senior vice president, corporate and business development for PalmSource. "We believe that the speed and reach of the innovative EDGE network will stimulate the development of robust, new Palm Powered devices and create opportunities for our developer community to add innovative wireless features to their Palm OS applications."

"Joining the Palm Powered Mobile World program allows us to collaborate closely with PalmSource in order to leverage its impressive Palm OS developer base. Together, we are developing complete wireless solutions that will take full advantage of the AT&T Wireless EDGE network — the fastest wireless data network in North America," said Jeff Bradley, senior vice president of business data solutions at AT&T Wireless.

Palm OS provides a flexible and efficient platform that is designed to enable hardware manufacturers and software developers to rapidly and efficiently create a wide range of powerful, innovative and easy-to-use smart mobile devices and software applications. Approximately 33 million Palm Powered handhelds and smartphones have been sold to date and Palm OS has attracted a large and loyal following with approximately 320,000 developers building applications for Palm Powered products.

About Palm Powered Mobile World
Launched in the Fall of 2003, Palm Powered Mobile World is a marketing program designed to connect mobile operators, infrastructure providers and software developers to efficiently bring Palm OS software applications and solutions to market, providing increased revenue opportunities and a superior user experience for Palm Powered smart mobile devices. More information on the Palm Powered Mobile World program can be found at www.palmsource.com/operators

About PalmSource
PalmSource, Inc. is the company behind Palm OS, a leading operating system powering mobile information devices. More than 33 million Palm Powered handhelds and smartphones have been sold to date worldwide. Industry leaders Aceeca, AlphaSmart, Fossil, Founder Technology, Garmin, GSL, Kyocera, Lenovo, palmOne, PerComm, Samsung, Sony, Symbol Technologies and Tapwave license Palm OS to create diverse mobile devices that meet unique customer needs. Palm OS has given rise to a large community of users, enterprises, developers and manufacturers, who together make up the Palm Economy. More information about PalmSource is available at www.palmsource.com, www.palmsource.co.uk, www.palmsource.fr, www.palmsource.de and www.palmsource.com.cn.

Palm, Palm OS, PalmSource and Palm Powered are trademarks of Palm Trademark Holding Company, LLC.

Safe Harbor Statement
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS: This press release contains forward-looking statements that involve risks and uncertainties, as well as assumptions that, if they never materialize or prove incorrect, could cause our results to differ materially from those expressed or implied by such forward-looking statements. Such forward-looking statements include, without limitation, statements related to the benefits of the Palm Powered Mobile World Program, the collaboration between PalmSource and AT&T Wireless, the EDGE networks, the smart mobile device market, the growth of the Palm Powered Economy and the features and benefits of Palm OS. The risks and uncertainties that could cause our results to differ materially from those expressed or implied by such forward-looking statements include, without limitation, our ability to successfully implement the Palm Powered Mobile World Program and to collaborate on multiple marketing and product planning activities with members of the program; AT&T Wireless' and PalmSource's ability to work with the Palm OS developer community to create applications optimized for the AT&T Wireless network; AT&T Wireless' and PalmSource's ability to successfully support the distribution of vertical applications to AT&T Wireless' target markets; AT&T Wireless' and PalmSource's ability, if at all, to timely align the Palm OS platform roadmap with AT&T Wireless' device and network requirements to cause device manufacturers to use the Palm OS platform to produce cutting-edged Palm Powered products that operate on the AT&T Wireless network and that meet end user demands; the ability of the EDGE network to deliver the anticipated speed and reach that will stimulate development of new Palm Powered devices; the realization of the anticipated benefits from the Palm Powered Mobile World Program, including but not by way of limitation, increased development of Palm OS applications optimized for EDGE networks, revenue growth for mobile operators and application developers, and accelerated growth of the Palm Powered Economy; the ability of hardware and software manufactures to rapidly and efficiently create a wide range of powerful, innovative and easy-to-use smart mobile devices and software applications based on Palm OS; the ability of the smart mobile device market to grow as we anticipate and our ability to benefit from any such growth; our ability to support, maintain and grow our developer community; our ability to compete with existing or new competitors, our ability, and that of our licensees and developers, to timely introduce new products to the market, general economic conditions in the U.S. and abroad and other risks and uncertainties contained in our public announcements, reports to stockholders and other documents filed with and furnished to the Securities and Exchange Commission, including our Quarterly Report on Form 10-Q for the period ended August 29, 2003, November 28, 2003 and February 27, 2004. All forward-looking statements in this press release are based on information available to us as of the date hereof, and we assume no obligation to update these forward-looking statements.