PalmSource's president, CEO and director David Nagel has quit.

No reason has yet been given but the handheld OS company said Nagel would stay on until mid-July to aid the "transition" of senior VP Patrick McVeigh into the interim CEO role.

McVeigh was appointed as head of worldwide licensing in February, coming from his job as CEO of Aliph, a developer of next generation audio and speech technologies for mobile devices. Before that he was also CEO of Omnisky, sold to Earthlink in December 2001.

McVeigh was also worldwide sales and marketing VP of Palm, which spun PalmSource off in October 2003. Before joining Palm, he had spent over 10 years with Apple.

Although the company said it would immediately start looking for a replacement CEO, it was only last week that the interim CEO of parent company PalmOne, Ed Colligan, was officially given the job.

Competition has intensified for both PalmOne and PalmSource recently. PalmOne is losing share of an overall declining PDA market, and PalmSource has been looking to make deeper inroads into the market for smartphone operating systems.

In February, PalmSource acquired China MobileSoft with an eye toward gaining smart phone and Linux expertise. Later that month, it introduced of a range of mobile phone software and third-party applications at the 3GSM World Congress in Cannes. New products included mFone for Smart Phone, a platform designed to run on Linux, and Feature Phone, which provides an interface and engine for telephone dialing.

In March, PalmSource launched two mobile phone platforms based on software from CMS: PalmSource Feature Phone for budget mobile phones and PalmSource MFone, Linux-based software for upscale handsets.