Is there some standard way of adding AV to Postfix?
clearly the best way is to add a wrapper program like amavisd-new or MailScanner which handles spamassassin and which ever combination of anti-virus programs you use.
The postfix list and primary author, Wietse will tell you flat out not to use MailScanner (there's something personal between Wietse and Julian, the author of MailScanner) but I found amavisd-new to be a PITA and just love MailScanner myself and have never had issues with integrating MailScanner into Postfix mail queue.
rpmforge has clamav/clamdb packages. MailScanner is available from http://www.mailscanner.info
Craig
agreed. mailscanner is ok.