I have TH AIS 1-2-call as well
http://www.ais.co.th/eng
http://www.one-2-call.com

To change languages, promotions, and activate Int'l roaming call customer service at 1175

you can check balance and refil account WITHOUT calling in.

REFIL press '*120*xxxxxxxxxxxx#' and then send/call/yes (xxx=refil code of course)

BALANCE CHECK *121# send ... balance check can be done from anywhere... I check my balance from Canada regularly

1-2-Call default promotion is as stated above

- once 25 baht is spent in 24hrs, remaining domestic local calls are 25% off. With this promo, each 300 baht added to the account extends the validity 30 days beyond the previous date. (I use so much airtime, my account is constantly valid for 1 year - the maximum. Very convienient as I can keep the same number each year)

- other promos include one that has 2 week validity maximum. IIRC it doubles your airtime so 300baht refil card counts as 600 (& 500 = 1000 etc).

As for Int'l roaming. I called last year. They asked me what countries I wanted. (S'pore, Malasia, Vietnam, Canada, & USA) They then asked me a few quick questions and I was hooked up. Easier than I could immagine. Now the hardest part is keeping Baht in my account. I get charged to receive a call outside of Thailand at regular LD rates. I guess the same for making calls. Very simple!