Crobat is a fast Pokemon (almost on par with Jolteon, Aerodactyl et al), with a high attack and good defenses; as well as resistances to Grass, Bug, Fighting, Poison and an immunity to Ground. The moveset for it really depends on what role you need it to fit in your team.
THE FR/LG standard is probably the best, and is pretty much the moveset described by 0mastar:
Crobat @ Choice Band
Ability:Inner Focus
Nature:Adamant (+Atk, -Sp.Atk) or Jolly (+Spd, -Sp.Atk)
- Sludge Bomb (For STAB, naturally)
- Aerial Ace (As above)
- Shadow Ball (For those pesky Psychic types, chiefly Alakazams)
- HP Ground/HP Fighting/Steel Wing (For those Rock-types

I prefer HP over Steel Wing for accuracy, but a defense increase ican come in handy)
Basically, you CB and you're away... easy enough.
Annoyer movesets are equally viable, though I prefer someone like Umbreon for that kind of role. Besides, Crobat fills the physical sweeper role quite well, and thats where its strengths lie. While not as used as other physical sweepers (Salamence and Aerodactyl being prime examples), Crobat is worth a look.
Just a tip... you might want to avoid Haze and Curse. As aforementioned, Haze is poor on Crobat, and is decreasing in use both ingame and through the metagame, in favour of pseudohazing techniques such as Roar and Whirlwind. As for Curse, it does augment Crobat's attack and help it last longer against physical attacks, but the sacrifice in speed is not well suited to Crobat.
Well good luck raising a Crobat, and let us know how it goes!
edit: just looked at Nine Thou's post and realised my suggestion is on that website.
