T-Pain iPhone App
Found this app via the Daily Intel's blogpost about Gossip Girl last week. In a nutshell, this app is like a karaoke machine and recording studio. Inspired after seeing a tiny, blond girl perform a Snoop Dog track at a karaoke bar, I decided to buy/try this app.
Also, the buying and downloading experience is cohesive (meaning, I'm not ported to another site to buy a track, and it's downloaded into my iTunes account). This app is self-contained, which allows a more engaging experience. Love that you have options for real time auto-tune, and it truly works better with the mic. After trying this app, I could really see its viral potential.
Last, bought the "I'm on a Boat Track" and it seems like the instrumental is louder where the profanities are. If you are a fan of SNL, Smule is hosting a contest: