Solution:
don't PIRATE software... just buy legitimate copy (iWork is only $79 dollars and is cheaper than Microsoft Office and there are alternatives to Photoshop like
Pixelmator,
Acorn (which is a whole lot cheaper than Photoshop while being easy to use and have around the same capabilities of Photoshop)... or if you looking for open source, GIMP, Seashore and OpenOffice/NeoOffice)
Also, downloading software from unsafe sources are most likely going to attract these kinds of trojans. Also, the trojan requires the user to enter the administrator password, it's not like Windows it will execute without the user knowing it, but most people will enter the password regardless unless someone knows for sure.
It's probably a good idea to get
Little Snitch which is more powerful than the built in firewall Mac OS X provides and can block applications to connecting onto the internet (although it can be naggy).