I did not know about Clamtk, that looks like a nice option, seems to have a clean GTK2 interface.
Some non-free as in freedom, but free as in beer options might be Avast Free for Linux:http://www.avast.com/eng/download-avast ... ition.html
AVG Free for Linux:http://free.avg.com/ww.download?prd=afl
Both have .deb files available, so you can just download the files, right click on them, and install with the Gdebi installer. I checked the deb's for both apps and all dependencies are met, on my system. You may have to install some packages from the repo to install on your system (though I doubt it), but Gdebi will tell you which ones.
NOTE: I have not installed, nor used, either of these packages. I used Avast on my XP box and found it worked just fine for me.