I have iphone 3G with wifi work ok but this morning my iphone can't find any signal of wifi.I check my wifi at home work ok and have restore it but in the end it just like it is can't find any signal of wifi.Is there have a solution for repair it?Can anybody help me,please?

Kenny, I have the same problem. Is your iPhone Jailbroken/unlocked? Let's try to identify the similar properties, it will help when someone figures out a fix. I've heard around that 3.1 should have this fix and that this issue is most likely software related.
It all started on 2.2.1, out of nowhere, the Wifi was lost. Still dont know how, but ever since, I've restored and pretty much did everything I read aroun. (Even the freezer, but no success)

I'm still on the lookout for a solution, and as soon as I find one, I'll post it all over so that people like us don't spend months trying to fix this damn bug.

Good luck, please let us know of any updates.

i have the same problem too, after jailbreak and use it for a few day, wifi start crazy. can recognize the wifi network but when try to connect, it's return message.
"unable to join XXX".
tried to restore to apple firmware, or custom firmware but no used.
i don't know what the hell is going on with my iphone 3G.