What Video Types Does Mac Support?

Hi, I'm new to mac. I've used Windows all my life and just recently received a free iBook G4 from a friend. So needless to say, I'm still figuring everything out. I have a video that I transferred onto my mac, but its a .wmv file. So I downloaded Flip4Mac (I think that's what it's called) and now I can view the video in quicktime. But I'd like to set this video as my screensaver. So I go to preferences, then Desktop & Screensaver, and click the screensaver tab. Then I click Choose Folder -> Desktop, and I see the .wmv file that I'd like to use, but its grayed out and I can't select it. I'm assuming this is because Flip4Mac only enables quicktime to play wmv files, but does nothing for screensavers. So, what video filetypes does a mac support, so that I can convert this video? Thanks.

Hello, you can give this a shot.
http://iscreensaver.com/

Sweet, thanks alot. ^_^