Cingular DOESN'T provide BES, no carrier does. However, a BES plan just provisions your BB to be able to use it on a BES server which you will be responsible for. So anywhere you go, you would need to be on a carrier that has a BES plan so they can provision your BB. I have the BES plan with cingular, but then I pay extra to have a hosted exchange with BES server, $19 a month.