On some of the pirated software sites, there is a copy of iWorks 09 that has a trojan horse in it. 

Note:  it isn't a virus, nor can it infect other peoples mac's ( One has to install the pirated software on one's machine for it to be infected)

To remove it, one can obtain a free tool from MacScan at:

Glenn Anderson

Client Services, IST

University of Waterloo

Waterloo, On

519-888-4567 x33327

anderson@uwaterloo.ca