Four months after Soulja Boy got his iPhone app [2]--which let users remix his songs--50 Cent gets his, dubbed "50's Sound Lab."

Only 50 Cent's app is part of a marketing campaign for Vitamin Water. Like Soulja Boy's remixer, the older rapper's free app [3] uses Moderati's music remixing platform Romplr, but users can only mix one song: "Baby By Me," 50 Cent's first single from his latest album, Before I Self Destruct. You can then post your creation on Facebook, send it to a friend, or enter the contest for a shot at winning a trip to NYC to meet the rapper and New York Times bestselling author [4] (for his book, The 50th Law [5].) 50 Cent will supposedly even pick out the best remix himself.

Even though the actual app and contest have little to do with Vitamin Water (the "flavor creator" Facebook app [6] was way cooler), at least we got a kick out of the literal interpretation of the song title in the promotional video.

[Via 50SoundLab [7]]