Thailand - more on AIS 1-2-1 Call
The details from BangkokTraveller are very good, and I was able to get a SIM card from the 7-11 next to my hotel.
What's important to note is:
- EDGE is the fastest speed for pre-pay SIM cards (or that's what the locals told me)
- Data access is only measured in time, so you need to turn on and off your APN, or you'll use up your credit.
I setup two APNs on my phone, one for AIS (called internet) which is charged at THB1 per minute, or using the pre-pay bundles mentioned in the other post. The second APN is called aisnodata and I set this one active when I don't need to be connected. I found a widget for my Nexus One which does this from the home screen.
This turning on/off data requires a bit of practice - my first THB100 vanished when I left the APN connected.