get a barron's or peterson's one if they make them. I find PR
to be too basic and good only for reviewing after you've had a full course and already more or less know all the material.
and coursenotes.org is your friend.
as for gov. I think US gov is pretty easy. I'm in it right now and depending on where I go to college this fall and whether they'll accept credit, I'll decide about whether or not to take it.