Sorry I lost the exact place in this long thread where I read this solution, but THANK YOU to the person who posted it earlier. I went into Settings, General, About, and OMITTED THE APOSTROPHE in the name of the phone. If your name is say, "Susie's phone", change it and get rid of apostrophe. I did this, powered phone off and on, attempted to re-connect to my home WiFi, and VOILA- it connected perfectly. (btw had already tried resetting the network settings, unsuccessfully). Only thing I notice is that when the screen closes for a period, the phone reverts back to 3G. When I slide open, the wifi comes back on. So perhaps this is not a permanent fix, but it does work now.
I called Apple and shared this problem, they found the discussion thread I gave them, and were going to send a report to the Apple engineers. Hopefuly this issue will be addressed in a future upgrade!