This is based on [Stack Exchange podcast # 25.](http://blog.stackoverflow.com/2011/11/se-podcast-25-mark-russinovich/) 

I really don't understand why there would need to be virus checking on uploaded files. It would generally be a bad idea to execute anything which was uploaded, so, so long as you make sure the files can't be executed... Granted, I also use Linux for my servers, so I leave the "execute" bit off.