Check out Test Masters at www.testmasters.com. I took a prep class with them and it helped me a lot.
Test Masters offers classroom courses and 1-on-1 courses for exams such as the GMAT, GRE, LSAT, SAT, PSAT, ACT, ISEE, Subject Tests and other exams around the country.
Also, if you click on the link below, you will automatically get $25 off any full length course or online course: http://www.testmasters.com/coupon.asp?id=LW144
Let me know if you have any questions.