Trolltech will be shipping a linux-based phone for developers in September. The device will be sold with a developer kit with everything (presumably) you need to write/rewrite software for it. It will connect to cell networks via GSM/GPRS and have builtin wifi. (Story here).
Depending on the price, I really think I want one of these. I’m thinking of using the wifi for communications over jabber+jingle and/or SIP in addition to web and email.
If I end up getting one, you can bet that I’ll be posting about it… you know, my birthday is in September 