I am in the same boat. Interested but also intimidated by the risks, potential falling bitcoin price, increasing difficulty, ASIC mining rigs only going to insiders or those willing to risk money waiting for delivery.
As long as you have a Radeon card w/ opencl support you should be good to go. Read up on cooling the card and be sure to monitor temperatures if you are going to give it a shot. If you have done any overclocking in the past you need to apply these skills here. Set up a performance profile in MSI Afterburner, or whatever you use for mining and other profiles for gaming, etc.
Assuming you are mining BTC:
Read around to see what others have done and what to probably expect from the make/model card in use. The settings for your GPU cores should be pushed up to the max stable. Lower the clock speeds on the memory as low as you can get them in order to reduce heat output. Test, monitor, test, and monitor some more.
Also look for a pool that does merged mining. Mine collects NMC as well for no additional effort and enhances the efficiency of the operation (not by much mind you).
Good luck
Here is a real noob question, what is "merged mining"?