If he is on the lease, you can not evict him, only the land lord can. However, they would likely not do this without evicting both/all of you. Your (ex)friend may not leave willingly, since their name would stay on the lease. You could leave, but your name would stay on the lease as well.
Sueing for back rent could also be tough. Does he pay you, and then you pay the land lord? If he pays cassh, does he usually get a receipt? If he always pays cash with no receipt it's you word against his that never paid the $1000
Best bet is to be a good friend for a day or two, and then get him to admit, preferably in writing, that he owes the money
How much longer is left on the lease?
Good luck!
http://www.judgejudy.com/SubmitCase/submitcase.asp
http://www.peoplescourt.com/home.html
Let us know when it's going to air!