Mining is one of the ways to get hold of Bitcoins. If your intention is to carry out GPU mining, you're going to need specialized software like GUIMiner.
The best alternative for GPU mining.
GUIMiner is one of the most simple and easy-to-configure GPU mining applications. It supports NVIDIA and ATI cards, and also allows you to carry out CPU mining.
Will I obtain Bitcoins with GUIMiner?
You have to know that GPU mining is complicated. The computing power required to mine and be rewarded with Bitcoins is very high, and your PC's graphics processing unit might not be up to it.
Use GUIMiner to mine alone or as a member of a pool.
But if you don't have an FPGA (Field Programmable Gate Array) or an ASIC (Application-Specific Integrated Circuit) chip card, your alternative is to use GUIMiner to carry out GPU mining. If you join a mining pool you'll have possibilities to obtain Bitcoins.