here is the best advice I've ever heard about sight reading.
I did that on the piano (that was strange at first to play those really, and I mean REALLY simple pieces with only whole notes ...)
and I begin to get my way on sight reading on the piano.
I do the same on bass and it works great too.
and yes, when you do it everyday, being true to yourself and your level of sight reading, knowing that it's not a contest and forgetting your pride, it works and progress are quick
here's the link:
http://www.youtube.com/watch?v=aASBNbeREEY
hope this will help y'all