To be profitable, which is becoming increasingly harder with increased competition, you will need a serious mining Rig, 1 or more, and an emphasis on more, GPU. The CPU is not that much of a concern, just the GPU's.  If you are doing it for a hobby and money isn't a concern, than you may break even or make a little. If you are doing it as a business, the competition is hard. Your best bet would be to join a Pool and share rewards - a fee of course. There are several out there. Deepbit is the largest known pool.

But if all you want is BTC, then the previous post is correct. The best thing is to buy them or sell something for them.


revision: Or steal them