It should work fine, but you don't need to go to a T~Mobile store to activate an account, just get a SIM and activation kit and you can activate your account online when you get it. http://www.t-mobile.com/shop/Phones/...Activation-Kit
Here it the kit you'll need, it is $1.99 with free shipping and whatever your states sales tax is.
Go here to activate your account http://www.t-mobile.com/shop/plans/ActivateCodes.aspx
when you get the kit and you can set up which plan you want.
You can buy your airtime from them or CallingMart.com. They usually have a discount coupon code about once a month, watch these forums or 'Like' their Facebook page and they post the new code there.