Need help finding an app

Iam looking for an application that allows you to change your phone number to anyone of your choosing when calling someone. For example: I could call you from my phone but i could make it look like your brother is calling you on your caller ID.
I had this app with my blackberry when i had tmobile. Since ive switched to sprint i havent been able to find this app anywhere. Can you help me please. :confused:

Bluff My Call, there are others check app world and the crackberry store.

Posted from my CrackBerry at wapforums.crackberry.com

Have you or anyone used bluff my call? How is it?