I've read all the posts on downloading movies, and they were things I was already doing. Check the size, bitzi, etc. I download until it's at a few percent and then right click > preview. I downloaded one movie just fine that would preview and played just fine. After that they've all said something like "quicktime does not recognize this file" or "bad public movie atom" or, most common, it will open in WMP and then say "Windows Media Player cannot play the file. The file is either corrupt or the Player does not support the format you are trying to play." Does this mean that it will or will not play on my ipod? The reviews on bitzi said it was a good file. Why does WMP do this? What file types *are* compatible? Please help, thank you!

Not 'all' file formats / files preview well before finishing. Keep in mind a file may not necessary download in sequential fashion, but perhaps parts of the middle & end & information for the operating system to read to understand it. Perhaps even that part has not downloaded yet & the file is thus not recognisable by any player at that time because the video player finds no information about beginning & end time, etc..

It sounds like you are 'maybe' missing codecs for each of QT & WMP.

Have you tried VLC player as a back up alternative to try? It's not a super large program, but has all the needed codecs built inside the program itself.
VLC - (click on link) _ (choose nearest mirror site) ... I personally use both vlc & Mplayer & QT as my main video players. MPlayer is very very similar to VLC but there's some small subtle differences between them one can do & the other can't. I use a beta or alpha / 3rd party dev. version of MPlayer, accessible by exploring the MPlayer's site options.

thank you! I'm trying that now, I understand what you mean and that should help. =)