Can't say for sure if it's really by Dr. Luke like it says, but I think it could be, and anyway it's a really hot song ;-)
http://rnb4u.in/968_5-Da-Coalition-It-Wasnt-Me-Prod--Dr--Luke-T-I---Usher-Demo.h
UPDATE: Uh-oh......the link won't work ;-( I'll try 'n find another one, as it's a really good song!
Ahh, got it now....it just copied wrong before:
http://rnb4u.in/968_5-Da-Coalition-It-Wasnt-Me-Prod--Dr--Luke-T-I---Usher-Demo.html
It's too much R'n'B for me! But I kinda like the chorus ;).