We are implementing a hosted Exchange solution that is running BES in thier environment of which we will be connecting to once we go live. I currenlty have a Blackberry with Sprint and another employee has a Blackberry with AT&T. Someone told me that we needed to get a higher tier internet service for the Blackberrys as the basic BIS internet package will not allow our Blackberrys to communicate with the hosted Exchange provider running BES. I have spoken to many people and nobody can give me a concrete answer. Do we have to pay AT&T the higher montly service fee for BES even though we will not using their BES server? Can someone enlighten me?

Here's your concrete answer:
Yes, you need the higher-priced BES data plan if you plan on using BES. Doesn't matter who hosts the BES. If you want to activate your device on ANY BES, you need the BES data plan.

(Also, wireless carriers such as AT&T do not host public BES servers at all.)

The quick answer from AT&T is yes. Mine went from $30 to $45. Why? . . . because they said so.

Excellent. thanks for the fast reply. does anyone know how much the monthly BES plans are for Sprint? I visited thier website but it states to call. i dont feel like calling them right now.

Sprint stand alone BES plan is $39.99. If you are on a bundled data/messaging plan BES is a $20.00 add-on.