Since I work with sound, and constantly swarmed into all sorts of music software, released on a cool program that has been made to communicate voice in online games, but it is compatible with IP-telephony software, VoIP and instant messenger (Skype, AIM, Yahoo, MSN, Google Talk, TeamSpeak, and other). The program deals with voice morphing. He changed out of all recognition in real time, and restore the original tone is almost can not be - can be great disguise.
For serious work provides integration with such monsters audio processing as Sound Forge, Vegas, ACID, Audacity, and many others. To work in the messengers and games have a handy Compact mode.
Voice changes on the fly, it can be used on only the modulation, but also all sorts of shifts, wrapping, and not to mention the effects on the Conventional like the echo produced in different virtual spaces, or background sounds (such as if you are in the transport or in the countryside, where the birds sing). It is a pity that the free trial only seven days before I stop playing. Now I think I buy?
Pruflink: http://www.screamingbee.com/product/MorphVOX.aspx.