i have t-mobile flex-pay and their policy for unlock codes are a 40-day minimum. After my 40-day they gave me an unlock code for my hd2 with out hesitation,and i didnt even buy the phone from them! talk about good customer service.
As an iphone owner currently on the AT&T network I did research T-mobile but as far as I know it doesnt work with T-mobiles recently launched 3G network. If there is a way please someone correct. The phone is currently Jailbroken (helps international trips)