The fake antivirus software that's currently targeting Mac users started out using the name MacDefender. It quickly changed the name of the application to MacSecurity (which we show in a video), and now has a new name: MacProtector.
The software is the same, and it's being server from a web page that looks like a Mac OS X Finder window. But the new name is probably an attempt to fool users, who may already have read about the first two versions.
No matter what it's called, though, the application still looks the same, as you can see in the screen shots here.