To bolster Benjamin's point....

Viruses for Apple including, but NOT limited to....

MacOS/nVIR - http://vil.nai.com/vil/content/v_99830.htm
MacOS/INIT-M - http://vil.nai.com/vil/content/v_99861.htm
MacOS/ZUC - http://vil.nai.com/vil/content/v_99863.htm
MacOS/CDEF - http://vil.nai.com/vil/content/v_99888.htm
MacOS/MBDF - http://vil.nai.com/vil/content/v_99829.htm
MacOS/INIT29 - http://vil.nai.com/vil/content/v_99858.htm
MacOS/WDEF - http://vil.nai.com/vil/content/v_99862.htm
MacOS/SevenDust - http://vil.nai.com/vil/content/v_99884.htm
MacOS/Simpsons@MM - http://vil.nai.com/vil/content/v_99102.htm
W97M/Antimarc@MM - http://vil.nai.com/vil/content/v_98325.htm
MacOS/CODE252 - http://vil.nai.com/vil/content/v_99832.htm
MacOS/MDEF - http://vil.nai.com/vil/content/v_99835.htm
MacOS/CODE32767 - http://vil.nai.com/vil/content/v_99838.htm
MacOS/INIT1984 - http://vil.nai.com/vil/content/v_99857.htm
MacOS/INIT9403 - http://vil.nai.com/vil/content/v_99859.htm
MacOS/Flag - http://vil.nai.com/vil/content/v_99891.htm
MacHC/Merryxmas - http://vil.nai.com/vil/content/v_99893.htm
MacOS/CODE9811 - http://vil.nai.com/vil/content/v_99896.htm
MacOS/Peace - http://vil.nai.com/vil/content/v_99831.htm
MacOS/INIT17 - http://vil.nai.com/vil/content/v_99834.htm
MacOS/NVP - http://vil.nai.com/vil/content/v_99836.htm
MacOS/T4 - http://vil.nai.com/vil/content/v_99839.htm
MacOS/ANTI - http://vil.nai.com/vil/content/v_99887.htm
MacOS/CODE1 - http://vil.nai.com/vil/content/v_99890.htm
MacHC/ThreeTunes - http://vil.nai.com/vil/content/v_99892.htm
MacOS/Frankie - http://vil.nai.com/vil/content/v_99894.htm
W32/Yourde - http://vil.nai.com/vil/content/v_100269.htm (can be carrier not be infected)

Plus "all"; MS-Word and MS-Excel and other MS Office Macro viruses

As for OS-X, it is a Unix BSD based OS that uses Apache and experiences *many* of the
exploits on the Unix/Linux platforms
BSD/Scalper.worm - http://vil.nai.com/vil/content/v_99539.htm
BSD/Exploit-Autofsd - http://vil.nai.com/vil/content/v_99388.htm
BSD/OpenSSH.src - http://vil.nai.com/vil/content/v_99680.htm
Linux/Slapper.worm.a - http://vil.nai.com/vil/content/v_99710.htm
Linux/Slapper.worm.b - http://vil.nai.com/vil/content/v_99710.htm
Linux/Slapper.worm.c - http://vil.nai.com/vil/content/v_99710.htm
UNIX/Exploit-Rogue - http://vil.nai.com/vil/content/v_99775.htm
BSD/Block.worm - http://vil.nai.com/vil/content/v_100670.htm
BSD/Walk.worm - http://vil.nai.com/vil/content/v_100196.htm

Trojans:
ChinaTalk
CPro
Fontfinder
MacMag
Mosaic
NVP
Steroid
SubSeven
Tetricycle
Virus Info


References:
http://vil.nai.com
http://www.ciac.org/ciac/bulletinsBy...bulletins.html
http://www.ciac.org/ciac/bulletinsBy...bulletins.html
http://www.icsalabs.com/html/communi...e/viruses.html
http://www.icsalabs.com/html/communi...rus/reference/
http://www.securemac.com/agax.php


Dave