PSjbiPAQ is a project mainly written in C, it's free.
PSFreedom port to iPAQ H3600 platform (H36xx H37xx & H38xx)
This is still work in progress.
Unfortunatelly the site handhelds.org is now down, so most of the available information has vanished. There seems to be ftp mirrors hosting the information.
What's needed
Warning -I take no responsability if your iPAQ get bricked. -There is no dual boot capability, although it is posible to reinstall WindowsCE.
Developers: