Tammy offers some tips on using Croak.it, a free web-based recording app for the iPad (and Android) that generates a URL for the recording. No login required, but you are limited to 30 seconds per recording. Check out her post for some ideas on how to use it.
The Croak.it website also allows you to record in your browser, and even add a bookmarklet to your menu bar. (Watch the short how-to video clip)