I've gonna be spending some time abroad and I'll definitely have Wifi. I have an 8100 right now, but will look into an 8120 should it meet my needs.

Basically, I'd like to use WiFi only (for $$$ reasons) instead of using the cell towers and paying roaming fees. Is there a way to essentially disable the cell phone capabilities and use wifi only?

For phone calls, some sort of VoIP software package would be perfect.

I'm still under contract so will keep my cell phone service with AT&T, but if I cancel my data plan while I'm abroad (for months at a time), would I still be able to get push email, web browsing, etc. over wifi?

I'm sure this has been attempted before or even discussed before. I tried searching, but point me to the appropriate thread if this topic has already been covered at length.

Thanks!

At this time there is no VoIP for the 8120 from AT&T (not even any 3rd party apps.) You can turn the mobile network off and just use wifi for data, though.

TMobile is the carrier to have if you want VoIP. Their UMA service is great for overseas travel.