Had the same problem at my families house after 3 days of working fine...Turned out I needed a new SIM card, which I got (for no charge of course) at AT&T and installed at Apple Store (both were next to each other in the mall)....just an idea...
When I was at a friends house today it worked perfect there, but for some reason the WiFi at my house is not connecting(actually it does have the check next to it, but it's just not dialing in or whatever).
Actually, I noticed it turns on when I make a call from my house, but when I end a call it goes back to EDGE. Can't figure it out, anyone have a similar problem with a possible solution? Edge blows, WiFi makes things so much easier.
So I unplugged my router and then I wasn't able to get onto the internet from my computer, so I had to call Lynksys to reset my IP. I have a pw set on it now and I typed it into the iPhone when it detected the router, but I'm still not getting WiFi on it and it has full signal in the settings. This is so freakin frustrating