This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
In either case (server or client) you would have to examine the virus-scanning package you have in mind and see what facilities it provides for automation like that. It's possible that the shrink-wrapped version you buy for under $100 would have no such facilities, but that embeddable versions might be available from the company for a higher price. Again, you would have to ask the company about that.
Obviously it's possible because I have seen it done, and no doubt so have you.
I am planning to have it on serve. So if I have a file on my server and user is trying to download it - it would be scanned for viruses by the server before offering user to download it. Similar to virus scan offered by Yahoo mail and similar. maybe, I can write to those AV companies directly.
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus