i talked with this person the other day they told me that an unlocked phone can go to any carrier. but i will try to get in touch with this person to answer your questions.
The storm 9530 was a verizon global phone, with a cdma radio for use in the usa and gsm radio (sim card) for use overseas with the verizon plan,. With it unlocked, any carrier's sim can be used in it, it can be set to GSM only, and it will work anywhere, At&t, overseas, whatever.