Samsung DIVE.

The Help page tells you how to set up the service. Unfortunately, T-Mobile has fucked up their version of the firmware, making it impossible to add a Samsung Account or register with this service.

See here for UK discussion

Fortunately it’s not too hard to update to the base Samsung firmware without voiding your warranty, as T-Mobile sends the phones directly to Samsung for fixing. T-Mobile Forum + links to instructions

These instructions take 10 minutes to implement

and upgrading to the leaked Gingerbread 2.3.4 also shouldn’t take too long.

These instructions are for the Samsung Galaxy S2