best audio recording software

i need a good recording software for my macbook to record lectures on

usually i use the word notebook template in microsoft office but half of my professors supply outlines so i don't have to take notes, i just want something i can refer back to and possibly add to my ipod so i can listen to the lectures on my trips back home

thanks in advance

I assume you will use the in built mic?
Audacity is free and ok, but doesn't natively save as MP3 for example.
Audio Hijack is also very good, and the Pro version exceptional.