well the file i'm talking about is the new episode of sm*llv*lle. i don't know if problems have cropped up with other files too, but it seems that if the file really is not readable than it must be done on purpose. I have finally been able to locate a version that according to bitzi lookup works.
As to what the file extensions mean it doesnt really matter... other than the fact that wmv and wma (windows media video file, windows media audiofile) aren't supported by most players, other than windows media player, but they aren't useful anyway.
AVI being interleaved, as far as I know, means that the audio and video are stored side by side not seperately. if it helps think of it as being interweaving rather than interleaving. Not that thats in any way important.
Mov is short for movie... clever huh? thats not really important either.
Anyway I have not spent much time figuring out how to copy dvds into avi format , which is probably the most compact format for quality movies. Try a program called VirtualDub,. the best way to get this is by going to http://www.divx.com/divx/create/divxpro/guides/?lang=en

this is the divx players users guide which gives you good instructions on how to convert files with virtual dub and includes a link to download it. It's not an easy program to use because it has a LOT of options. It's quite good so give it a shot, but really you need the users guide.

As for ppl downloading too slowly... maybe you should limit the number of uploads you get. you can change that in the limewire preferences somewhere.