ART has some rpms you can use to accomplish this. It's what I use on my servers without any problems, and you can set it up so that the individual users still have some control. Control over everything except the global Delete If Over setting.
Look in Scott's forum there and you'll see some different solutions. Personally I use a combination of clamd (virus protection), razor-agents, pyzor, qmail-scanner and spam assassin, with SA_DELETE enabled.