The company has just released a beta of avast! Free Antivirus for Mac for download and testing, and like the Windows version of the software, it looks pretty good. Avast has been a longtime supplier of a free (for non-commercial use) antivirus package for Windows that is unobtrusive and fast, so it was with a great deal of interest that I read a PR blast from the company this morning. Apple released Security Update 2011-003 yesterday with protection from the MacDefender malware and its variants, but some of our readers might want to do more to protect their Macs from malware.