I don't know of a leather case, but I know there is an Otter Box for the curve 8330. Those basically make your CrackBerry indestructible, water proof (not in water, but from rain and splashes) as well as shock proof. just go to otterbox.com its like $50 but it will save your phone couple times over...
i got mine from the verizon store. simple leather holster with a swivel. here.
it's working well for me so far. the ratcheting clip is not so tight though, in that it tends to swivel just a bit. not so much when it's on, but belt clip is really tight, so when taking it off or putting it on it tends to swivel by a position.