PScan: A port scanner for PalmOS Devices.
This scanner is being developed by the Blue Collar Hacker's Union and is meant to be built using GNU tools (PRC-Tools, specifically), to be released under GPL.
OMMP is a community driven open source platform for developing mobile mashups (aka moshups) for mass-market devices. With OMMP, you can create fully functional widgets/applications that work on almost all mobile devices within a few hours.