Agreed with smmmu.....from my understanding the GRE is only a minimum threshold, after that they dont care specially for CS. The CS GRE would help you to prove that you meet a minimum criteria (it really helps if you are coming from a different background), but as an undergrad in CS I dont think it count much.
What matters is letters of recommendation (find someone well known in the field, if there arent at your school find an research position with someone at another school) and research experience. It doesnt have to get published in major journals or anything, just prove them that you want to do what you are supposed to do and prove them that you can do it.
Good luck!
