Avoid these people like the plague! If you do get a key to let it run, most likely it won't activate. Besides that, how do you know if it is clean or not (viruses, worms, etc.).
And as Mark said that once they have your card number, you just might as well kiss your identity goodbye.
Therefore, in the long run I have found the least expensive software is buying at retail from a trusted source.
I learned this some 15 years ago, swapping software with friends. No more, my files and my time are more important than saving a few dollars, not to mention my integrity.
Besides that, if you have any legitimate version of Photoshop, the upgrade to CS2 is only $150.00. A cheap price for peace of mind.