Blackberry
Blackberry Messaging from Research In Motion offers enterprise wireless messaging on the Blackberry device of your choice, including the Blackberry Curve, Pearl, or 8800 series devices (and many others).

Imagine...integration of email, phone service, data, applications, and games all on your handheld device. Hosted Exchange with Blackberry service form Research In Motion provides all this and...

• Easy setup. Get started in minutes, with simple instructions.
• Fully-managed. No servers to buy and maintain, no licenses to purchase and track.
• Low monthly fees. A small setup fee and per-user charge - no capital investment.

Sample list of supported phones: