Audio is not usually something I like to do -- I have a hard enough time leaving voice mail messages! That said, there is certain value in recording short instructions that could be linked onto a web-page, or as is suggested in the 23 Mobile Things section for audio, interviews or book reviews or audio essays.
Audioboo and ipadio both were easy to use. I was pleasantly surprised to see that instead of the limit of 3 minutes, the version of Audioboo that I downloaded allows up to 10 minutes of recording.
Audioboo also has a audio loudness meter that you can watch as you record, and are able to adjust the recording volume accordingly. It also has an extremely simple audio snipping tool -- as far as I can tell you can snip off the ends, but not pieces in the middle. You may or may not be able to do more precise editing on the website itself. Ipadio was more simpler to use -- just a big "target" button, no audio loudness meter, no audio snipping tool, etc. You can add multiple images to the recording, a title, summary and location -- same for Audioboo as well.
Both Audioboo and ipadio rely on their website for additional functionality -- minor editing and broadcast settings. You also have to go to the website(s) in order to delete any recordings you made as well, which is a bit of a bummer/hassle.
For the ability to do quick, simple recordings that can up uploaded or embedded into websites they both look very useful -- Audioboo for short recordings, ipadio for longer.