I dont think in call voice changer exists yet. Same question asked over at XDA:
voice changer for ppc exist??
Is there anyone out there who knows if there is any software that can change your voice while calling?
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kyphur 
Moderator
Join Date: Dec 2005
Location: Chicagoland
Searching would reveal that this question has been asked before and the answer is still no chance because Windows Mobile doesn't have access to the phone audio.
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