If you are a home user and your platform of choice is the Mac, you can find a rather elegant and free OS X anti-virus solution in PC Tools iAntiVirus.
Note however that iAntiVirus won’t catch any non-mac threats, so if someone sends you a file with a windows virus you are still at risk of passing it on to friends. Nevertheless, it will catch known Mac viruses and trojans and since there are fewer of these on the Mac side, the scan will generally run at a good clip.
The company also has a subscription version of the tool with technical support for business users.
Alternatively, all Mac users can look at ClamXav (see tomorrow’s post).
Also see Part 1 & Part 3 of this series.