TwiXtreme touts itself as an ad free, cool client for BlackBerry users. The screenshots of the interface looked clean and easy to use. (I say this since I am just loading it for testing).
You can do quite a few things with the client:
- see trends
- get direct messages
- find nearby tweets
- upload pictures
It takes advantage of the screen real estate on the devices and the only restrictions seem to be the OS version, and not type of device itself.
The client is made by Xtremelabs, so you should pay them a visit and see if they have anything else you need since this is free.