Found a nice one for about $10 which is generic from a phone store. Those swivel clips always break on me since I break mine gettting into and out of cars. Get a holster with just the metal clip (mine is leather covered). It's less convenient and grans your side since it does not swivel but you will not have your BB detach from your side while entering or exiting your vehicle.

I had a phone replaced when mine came loose in the driveway and I accidently backed the vehicle over my phone (older phone). I swore off the swivel clip holsters ever since. I tried the RIM-branded one (swivel) since I immediately wanted to protect my new 8330 but it broke at the swivel on the 2nd day :(. I've used the BB "Pocket" which really isn't that bad, until I found a non-swivel case at a local phone store. It cost all of $10 and fits my Curve very nicely.