Last night the wireless on my iPhone "stopped working", I simply see no SSID's listed in the network browser.
Manually specifying details doesn't work either; monitoring my laptop's ad-hoc network using iwevents shows no packets from the iphone.
Google revealed quite a few people having the same/similar problem, with the typical kind of solutions appearing; reset network settings, full-restore firmware, have phone replaced by http://www.apple.com/au/retail/sydney/">Apple Store, etc.
Resetting the network settings didn't work for me (appears to be more relevant to the older iPhones).
I have successfully restored firmware 2.2.1, and still no wireless happytimes.
Maybe time to visit the Apple Store... aaarg.