Is there an android (froyo) app to change my voice when calling?

[darkflashworks]

Now i don't mean that i have to call trough a company(and pay them also money), i know it is possible on the phone because there are talk to santa and such apps that change your voice.

plus the cheap chinese fake iphone's have this app so android must have it too

so i dail a number, select a voice tone and then prankcall my friends