I'm realizing that traveling internationally with a cell phone as Internet access isn't as slick as I had thought. Any phone brought into Costa Rica, for example, won't work even if it is quad-band GSM.

AT&T is pretty expensive for a data connect plan, T-Mobile offers Edge access, which is slower, but only 19.99 a month, all you need for that is an unlocked GSM device that is at least Tri-Band. Make sure the phone is tetherable (Most new phones that are unlocked and GSM are).

I'll be traveling a lot soon and I'd like to get a cell phone that will allow me to make calls and get my laptop online all over the world. From what I understand, I'll need a GSM phone and provider. In the US, I think my choices are AT&T or T-Mobile.

I'd rather not pay for a data plan if I can avoid it. I'll be using the cell phone to get my laptop online pretty infrequently and a slow 14.4k speed would be fine. I've read that Verizon and Sprint allow you to dial up without a data plan to a 14.4k connection and only use your cell minutes, although it isn't advertised. Do either AT&T or T-Mobile provide anything similar? Would something like that work in both analog and digital reception areas?