Press Release

PalmSource Introduces PalmSource Installer

Facilitates the online and over-the-air delivery of over 20,000 Palm OS software applications

MUNICH, Germany, PalmSource™ Euro DevCon, September 28, 2004 — PalmSource, Inc. (NASDAQ: PSRC) provider of Palm OS®, a leading operating system powering next generation mobile devices and smartphones, today introduced PalmSource Installer, a new Palm OS application installation technology designed to streamline the online and over-the-air (OTA) download and install process of Palm OS applications onto Palm Powered™ smartphones and other wireless devices. As part of PalmSource's effort to make software titles more easily accessible for end users, PalmSource Installer can minimize the complexities commonly associated with loading software by providing one-touch software download and install functionality for Palm Powered smart mobile devices.

"We believe PalmSource Installer will extend our lead in providing best-in-class solutions that enable our Palm Powered partners to capitalize on the growing smartphone market," said David Nagel, president and CEO of PalmSource, Inc. "By making it simple and efficient to download applications, this breakout technology can help broaden the reach of Palm OS software applications and drive worldwide adoption of Palm Powered smart mobile devices."

"PalmSource Installer is a great solution that will enable us to build on our commitment to innovative wireless solutions for Palm Powered smart mobile devices," said Douglas Edwards, vice president of Handmark. "As a Palm Powered Mobile World partner, we look forward to continued innovation on the part of PalmSource to bring solutions that generate revenue opportunities for its partners."

PalmSource Installer offers registered Palm OS software developers and Palm Powered Mobile World operator partners the opportunity to deliver a superior user experience for Palm Powered smartphones and other wireless devices and gain greater exposure for their products. By enabling easier and more efficient software installation, PalmSource Installer minimizes technical support operations for software developers, freeing up resources to bring new Palm OS software applications to market. Palm Powered Mobile World operator partners report they gain increased data usage and ARPU on their wireless network by providing their customers with software applications that are easy to download, install and manage on a Palm Powered smart mobile device.

PalmSource Installer is designed to allow developers to bundle their Palm OS software application, support files and desktop components into a single, compressed software package that a user can download and install with a single touch of a button, whether via a HotSync™ connection to the PC or while on the go, via OTA delivery. PalmSource Installer is automatically downloaded whenever an end user downloads a PalmSource Installer enabled application package. In addition, PalmSource Installer is designed to leverage the ease-of-use of Palm Powered smart mobile devices to intelligently detect a user's device requirements, including memory, screen resolution and default languages to automatically install the appropriate files tailored to the device. The software applications optimized for online and OTA delivery to Palm Powered mobile devices draw from the more than 20,000 Palm OS software titles available today and found in the PalmSource software store located at www.palmsource.com/software.

The public beta version of PalmSource Installer is free and available to registered Palm OS software developers in the PalmSource Developer Zone at www.palmsource.com/developers. PalmSource Installer supports Palm Powered devices running all current versions of Palm OS.

About PalmSource
PalmSource, Inc. is the company behind Palm OS, a leading operating system powering mobile information devices. Approximately 35 million Palm Powered handhelds and smartphones have been sold to date worldwide. Industry leaders Aceeca, AlphaSmart, Fossil, Garmin, GSL, Kyocera, Lenovo, palmOne, QTech, 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 Powered 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.

Copyright ﾂｩ 2004, PalmSource, Inc. PalmSource, Palm Powered, Palm OS and HotSync are trademarks or registered trademarks of PalmSource, Inc. or its affiliate in the United States, France, Germany, Japan, the United Kingdom, and other countries. All other brands, product names, company names, trademarks and service marks are the properties of their respective owners. All rights reserved.

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 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 regarding the features, functions and benefits of PalmSource Installer. 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 the ability of PalmSource Installer to provide the anticipated benefits such as the streamlining of OTA download and installation of Palm OS applications onto Palm Powered smartphones and other wireless devices and the accessibility of more software titles for end users; the ability of PalmSource Installer to enable Palm Powered partners to provide best-in-class solutions and to benefit from the anticipated growth in the smartphone markets; end user adoption of OTA delivery of applications; the ability of PalmSource to grow and maintain its developer community and to compete with existing and new competitors; the continued growth of the smartphone and wireless markets and the penetration of these markets by PalmSource and its licensees; 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 Annual Report on Form 10-K for the period ended May 28, 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.