Does mac's need virus protection
In General 3rd Party AV Software is Not Required as Mac OS X tends to look after itself.
See Here > Antivirus Discussion
The Safe Mac > http://www.thesafemac.com/mmg/
To keep your Mac Happy...
Have a look here...
More Info Here > The myth of the dirty Mac
Helpful Links Regarding Malware Protection
An excellent link to read is Tom Reed's Mac Malware Guide.
Also, visit The XLab FAQs and read Detecting and avoiding malware and spyware.
See these Apple articles:
If you require anti-virus protection I recommend using ClamXav.