Of all the things I've learned about so far, audio is probably the area for which I have the least need or interest. I read a little about each of the three suggested audio apps and none really inspired me, but I thought I'd better download SOMETHING in order to complete this thing.
So I downloaded Audioboo and created a single sample recording, and it appears to perform as expected. I don't quite see the attraction in sharing homemade audio recordings in this age of instant video, so the social aspects of this app are kind of lost on me. My iPhone also came with a microphone app that seems to perform the same basic function as these audio recorders. While I've used it perhaps a handful of times in the years I've had my phone, I can definitely live without it, and in fact I more often than not forget that it exists.
I guess I have very little meaningful to say about audio apps since I can't imagine when I'd ever want to use one.