I'm selling a a blackberry to a friend without sim cards but the phones are former AT&T wireless phones. Will the new owner be able to use these phones on the cingular network as old AT&T phones with a sim from cingular/AT&T after porting their existing phone number over from another carrier? Is there anything else I should be or should make the new owner aware of before sale?

Thanks for any info...I tried a search but apparently kept getting post for people trying to sell their phones here.

Ensure that you have removed the device from an active weblcient account--otherwise they cannot use it again on another account.

Be very careful when selling an old AT&T BB. AT&T BlackBerrys work only with blue AT&T/Cingular SIM cards. It can be unlocked to work with Cingular or another carrier's SIM cards by GSMLOCKER or Bongo Wireless.