The best way to get Bitcoins at this point is to either a) buy them using your favorite fiat currency or b) sell a product or create a service and accept payments in Bitcoins.

Mining for Bitcions with a CPU or even thousands of CPUs is a total waste of time and energy.

Mining for Bitcoins with a GPU or even dozens of GPUs will soon be a total waste of time and energy.

Bitcoins will soon be mined using custom ASICs created specifically for that purpose but getting on the waiting list to get one of the ASIC units at this point is also probably a total waste of time and money.

Let me know if you have any more specific questions.