OK, something isnt right, here. This site, and serebii, both said that Luxray learned Crunch at lvl 35 and thunder fang at lvl 42. I was training my luxray and noticed tha he learned thunder fang at lvl 35 and crunch at lvl 42. I think this site is wrong.
Yeah our moves thing is probably out of date, there were some changes in HG/SS.
In Diamond/Pearl, Luxray learns Crunch at L35 and Thunder Fang L42.
In Platinum/HeartGold/SoulSilver, they are reversed.
Try Pokemon marriland.com because it shows you all the pokemon and the moves they learn and at what level.