avi85 -- sorry I stepped out and couldn't help your search for the BSA unpacker but I'm glad that worked!
[Edit]
Sorry, didn't see your additional question. I'm not sure that there is any great way to keep it from 'skipping' when loading new areas. I've heard of people doing a couple of things. First, you could try a faster hard drive, though I doubt that this will completely eliminate the issue. I'm not at all certain but part of what is going on when you actually load a new area is swapping out some of the stuff in the GPU memory. One of the alternatives is to alter the Oblivion.ini file to load more surrounding territory by default. The problem with this approach is that it really doesn't 'fix' the issue, it just makes it less frequent. I.e. you will still get 'loading' messages but they will be fewer and farther between at the expense of being longer.
The loading issue, I think, comes back to the GPU's memory: swap a little pretty frequently, or swap more but less often. Either way you'll have some loading issues. Since the gameworld is seamless, there is no way it all can be loaded into the GPU's memory at once.
[/Edit]