Welcome to the forums.
Firstly, I'd recommend reading through the first couple of pages of the Beginners forum - your question is asked and answered several times per day
Still, I'll try to answer for ya.
Bitcoin mining these days is the province of specially made Bitcoin mining machines, usually referred to as ASICs (which stands for Application Specific Integrated Circuit). Realistically speaking, unless you have a lot of money to invest to get started, it's probably not going to be worth it for you, and you'll end up losing money.
However, that doesn't mean that mining is dead. You can still achieve good results/profits by mining alt coins (also known as Scrypt coins) with your current computer hardware. There are a million guides for this, including the one linked in my sig (which is only partially complete). The idea is to mine an alt coin of your choice, and convert this to Bitcoin via currency exchanges like Cryptsy. There are several mining pools which do this automatically for you. Two worth checking out are
www.clevermining.com and
www.middlecoin.com.
I recommend you read the "Getting started" section on my site - not blowing my own trumpet, but it's specifically aimed at people who are unfamiliar with mining and its associated jargon. It might help
Rit.
