VoiceJam is a real time loop based mixer and recorder with pitch correction.

You can use it to create an entire song with your voice, simulating bass lines, melodies, rhythms and sound effects, all in one pass.

Main Features:

• Universal App with iPhone, iPod Touch, and iPad HD support
• In-App Purchase of HardTune Vocal FX
• Undo, reverse, 2x, loop mixing, and instant re-triggering.
• Performance Recorder
• Share performances online with high definition SoundCloud uploading.
• Easy to follow audio tutorial
• Support for AudioCopy/Paste

This is an entire song produced on VoiceJam:

New in v1.2.60

• Improved SoundCloud sharing, supporting posts to Twitter, Facebook, Tumblr, and Foursquare.
• Various fixes to improve iOS 5 support.
• Fixed scrolling & selection issues when when trying to select from a long list of previously stored sessions.

New in v1.2.50

• Added an in-app purchase for reverb modeled from VoiceTone R1. Choose from several different room simulations, from a clean studio sound to huge arena reverberations.
• Now has a smaller memory footprint.

New in v1.2.01

• Added In-App Purchase capability for buying pro quality vocal effects, the first available being VoiceTone C1: The infamous HardTune pitch correction effect as well as gender bending emulated from VoiceTone, TC-Helicon's world renowned line of stompbox effects for singers.
• The input audio waveform now turns yellow when you are close to singing too loud for your device to handle. When it turns red you've exceeded the volume limit and your recording will probably sound distorted. Unless you are intentionally going for distortion as a special effect, back off a little when you see the waveform turning red.
• Added Shots Mode, allowing instant re-triggering akin to playing your loops like samples on a drum pad.
• Added a live performance flyover for the new loop mixer and other controls.
• Added a loop mixer for non-destructively tweaking the level of each loop.
• Added a High Quality, uncompressed SoundCloud upload option.
• Share An Idea Link: Your feature requests will go directly to TC-Helicon’s development team.
• Added Mic Mute. Sometimes you want to jam on some pre-recorded loops without worrying about what’s coming in on the microphone.