Im also having problems with my Ipod touch.
It works fine at home but if i forget to turn wifi off when i leave the house (for work) it seems to get stuck and needs a re boot.
It will connect to another network and it shows this in the wifi page of settings but the details page has nothing on it and i dont get the blue bars showing on the main screen.
If i re start the ipod it works fine. Same thing when i get home. If ive been using BTopenzone (for example) outside and just leave wifi on when i get home i get the same result. It needs a re boot. just turning wifi off and on doesn't do it.
Its only been since i upgraded to the latest FW that this has happened. I konw its not my router thats the cause.