you won't be able to just plug the SIM into a Sprint 8830 World edition and use that becuase the 8830 Uses CDMA in North America, the SIM card is only for using the phone overseas, as the 8830 lacks the GSM radio frequencies used in North America.
Other than that the sim will work in any unlocked GSM blackberry.
Yeah. I use a t-mobile SIM in an unlocked AT&T 8820. If your SIM is active, just pop it into the device and go. The only caveat is that the WiFi will not work to make calls-if your AT&T device has WiFi.