Alright, For those of you out there that desperately want to be able to sight read better, you have to try this site. You can pick the difficulty of rhythms, different meters and set the tempo. Then you can play them on your own with your own metronome, or play along with the computer demonstrating the right rhythm. Best of all, It's FREE!
Improving your sightreading is 98% about your ability to read rhythms.