CFFile Upload and Virus Scan

Hi,

I'm trying to see if anyone knows of any free or low-cost virus scanning solutions for file uploads.   I have heard of some command line scanners that you can call via the <cfexecute> tag and this seems like a viable option for me, but I'm wondering how do these command line scanners get updated with the latest virus definitions?  Is it just like regular virus software where you can set it to autoupdate?

My goal is to allow the user to upload a document to a temp directory, kick of the virus scan once the file is uploaded, and when the virus scan is complete, I'd like to somehow notify CF so I can move the file to it's final destination directory.

Can someone steer me to a command line virus scanner that is maybe free or low-cost?  Or are there any known  webservices where I can send the file to and maybe get a response back?  I won' be allowing files larger than 1MB so maybe that's an idea.

Any help or thoughts appreciated

-Westside