I'm using the Eye-Q computer program (google it). Personally, it's helped me out a lot because I used to have trouble finishing RC and LR in time. But be careful, with any speed-reading program you have to focus on actually remembering what you read (not just blazing through words as fast as you can). What makes it even tougher for the LSAT is that you also have to understand argument strucutre while under time constraints. Your speed for doing this will rise, though, just not as fast as your WPM.
Has it occurred to anyone that the problem is reading too fast? I mean, you say you have to reread everything; have you tried slowing down?