I just found out about this: http://www.virustotal.com/advanced.html#browser-addons
Its a firefox/chrome addon where you can scan files you want to download before you do. Seems pretty handy to me.
For more info: visit this.
If the new layout is here, I think it would be cool to have a page about viruses, false positives etc.
this would definetly be something I'd like to see mentioned more often. Then people might actually try to confirm a virus before posting all over!
(not that anything here has a virus)
They also have an application that allows you to do this, no matter what browser you're using. I'm testing a build of it at the moment, and will be putting a dev test up as soon as possible.