SoundCloud is an online service for recording, hosting, and sharing audio tracks. You can use SoundCloud to upload and share audio recordings that you have stored on your computer. SoundCloud can also be used for directly recording a spoken track. Audio Memos is an iOS app for creating and sharing audio messages. The app is available in three versions. The free version is limited to 3MB recordings, the $0.99 version is limited to 15MB recordings, and the "pro" $9.99 version has a nice selection of audio editing tools built-in. Some of the features that are available in all three versions of the app are automatic pause if a call comes in while you're recording, recording volume controls, and recording even when your iPhone or iPad goes to sleep.
Audioboo is a free tool for
creating audio messages to share on the web. Using Audioboo you can
record messages on your mobile device using Audioboo's free Android or
(from Free Technology for Teachers)