Anti-virus for RHL

We use sophos:

http://www.sophos.com/support/knowledgebase/article/143.html

You can use sophos, trend micro etc.

if you want a freebie, go with ClamAV.
other best commercial one is nod32.

I really like Clam AntiVirus. You can read about it here: http://www.clamav.net/

On our Linux mailserver running Postfix, we run Vexira Antivirus for mailservers from Central Command http://www.centralcommand.com/index.html
Another good one is F-Prot from Frisk Software at http://www.f-prot.com/
Both offer Linux versions of their software, are reasonably priced and can be updated over the internet. We update both hourly since we have Vexira outside the firewall and F-Prot inside the firewall.