Cohdoo, the company that makes the iPhone whiteboard magnets that I've posted about have just released Highlight a nice iPhone app for voice recordings. It's aimed at helping user researchers record interviews, and is just as useful for recording meetings and conference talks.
To start new sessions, press the New Recording button, and during the recording you can tap the huge green Mark Highlight button, which I could see being useful for marking new questions during interviews, or marking sections of conference talks. Afterwards during playback, you can press a marker to jump to it, and swipe a marker to label it. You can then sync and access your recordings via iTunes, or email the audio recordings. Really nice app. I can see myself using this for more than just user research recordings.
More info in the App Store or on the Highlight site.