Off-site: avast! Linux Home Edition represents an antivirus solution for the increasingly popular Linux platform. The Home Edition is offered free of charge but only for home, non-commercial use. Both of these conditions should be met. I've found an ebuild here: http://code.google.com/p/gentoo-china-overlay/source/browse/#svn/trunk/app-antivirus/avast4workstation The ebuild looks good and I'd like to propose adding it to the portage.
I can't find a desktop version anymore (and it was useless anyway), so this request is obsolete.