HelloMobile GSM SIM (and the future of Sprint's MVNOs)

Will do

> also if you do by chance have a T-Mobile locked phone would be good to know if the SIM works in those. i have heard but from a possible not so reliable source(from inside the carriers but far more more knowledgeable on business than anything technical) that GSM/T-Mobile SIM's on at least some MVNO will not work on T-Mobile locked phones as has always been the case for T-Mobile MVNO SIM but rather would require phones to be unlocked.

I do have T-Mobile locked phone and I will check this point. But as far as I know, if the phones is locked to T-Mobile Proper (not to T-Mobile Prepaid or MetroPCS), you can use MVNO's SIM in this phone.