iOS: Instacorder is a dead-simple app that will instantly email voice memos to yourself for reviewing and organising on your computer. The first time you open the app, you'll be asked for your email address, after which you'll simply hold the huge recording button to enable the microphone. As soon as you let go, the voice memo is instantly sent to your email.
While you could always use an app like Evernote to create and organise your voice recordings, sometimes there isn't time to categorise and title a new note. Instacorder excels by simply focusing on recording, leaving you to sort and organise the memos once you get back to a computer.
Instacorder is free, but a $0.99 version will unlock similar one-touch functionality for emailing photos, as well as stripping out the ads.