I found and app called 'Disco' while browsing macworld, and it is really quite incredible! all you do is pop a disc in, drag files in the window and press burn. It will tell you if it needs another disc, you don't have to fiddle with any settings either. Even cooler, is the fact that when a disc is burning, smoke comes out the top of the window! you can move your mouse through it and it will react accordingly as well as blowing into your microphone. I highly reccomend you get it if you don't have toast.
BTW: althoug it is not free, it is still only US$19
BTW: althoug it is not free, it is still only US$19