If it's a zip file you won't be able to preview it. You'd have to extract it first, I'm pretty sure. Sorry... I just assumed you were downloading a music file

You really have to be careful with .zips. Sure, some are ok but a lot are not. From what I understand, they're pretty easy to infect. Like exe files. Have a read through this
http://www.gnutellaforums.com/showth...threadid=41432

If you absolutely must download zips, make sure you do scan the file with your AV program before opening. I probably sound like a broken record, but so many people end up with a sick computer after careless downloading