Where is Free Spyware Removal for Macs?

I haven’t found what I’m looking for yet: a free anti-spyware for Mac computers. (Yes, it’s true I’m afraid, I use both PC and Mac, for awhile I even dabbled in Linux. I know for those of you in the die-hard polarized-camps of Apple versus PC it’s hard to believe, but, in fact I’m so bi-OS sometimes I forget what kind of computer I’m working on. It’s a tool, not a religion.) And unlike some Mac users, I do believe running in virus software on my ibook. There are malware authors out there in cyber-space who specialize in Apple viruses and spyware, fewer in number, perhaps, than the PC bad guys, but still enough to put our computers at risk. Prevention is so less messy and so much preferable than cleanup. I use Virex from days when Apple included it in their Mac services. When Apple stopped sending updates, I found a site where I can download them for free. However, I can’t seem to find a free anti-spyware for Macs. If any of you readers know of one, please let me know.