Skype Voice Changer allows you to modify the sound of your voice in real-time, while you're having a Skype conversation with your friends. Now with additional features, such as the ability to record your Skype conversations, or play back pre-recorded audio files during a Skype conversation, you can use the Pro edition of Skype Voice Changer. It's completely free, and you install it by visiting the Skype Voice Changer Pro site