First off... please avoid posting the same topic in five different places, it's a little annoying to the users of the board. I think this topic belongs best in the "Prospective Physics Graduate Student Topics", so I will respond to it here
I think physics graduate school is a really great goal. I know somebody else who made the transition from computer science to theoretical physics so it definitely can be done. To study, he used the "Feynman Lectures" and the "Practicing to take the Physics Test 3rd edition".
The two key things to focus on are learning the basics and practicing for the PGRE specifically. It's good to bear in mind that everybody approaches these two differently, but personally, I think the "Feynman Lectures" make a really good conceptual introduction to the subject for somebody who hasn't had any physics training, however, it would be considerably cheaper to just buy slightly old editions of the physics textbooks or just check them out from your library. Anyways, just so you know what you're up against, the basic categories which appears on the test are as follows:
Electricity and Magnetism
Some random advanced stuff
Once you've gotten the basic concepts in these areas down somehow, you'll want to start practicing multiple choice problems similar to those which will appear on the PGRE. "Practicing to take the Physics Test 3rd edition" is out of print and very expensive so it's best to just download them from here
. Also, I'd recommend reading this article
for other ideas on which problems to practice with.
Best of luck!!!