Not a stupid question, but
currently there are NO viruses for OS X in the wild. There have not been since OS X was released back in 2000.
As noted by the other poster, Norton makes an antivirus suite for the Mac but it is a resource hog and really serves no other purpose that to prevent you from passing along any Windows type viruses that you receive attached to an email.
The Windows viruses do not run on OS X.
If you want to feel good about yourself and feel the need to protect those using Windows, you could always download a copy of CLAMXAV. This is a free piece of software that finds Windows viruses as well as being ready to find the first OS X virus.
Spyware is currently non-existent too. I know of no Mac Anti-Spyware software.
Congratulations on your decision to get a Mac.
If you have any questions, just holler