iOS: Recordium is an audio recorder and editor all rolled into one simple, powerful tool. The app also lets you annotate, mark up, highlight and share your recordings, and back them up to DropBox, Evernote or a range of other storage services.
Recordium is free for a limited time (until 1 June), so if you're interested in the app, grab it now. it's also a universal app for the iPhone and iPad, so grabbing it once makes it available for all of your devices. Recordium records audio in MP4 (although you can opt to save in WAV, CAF or AIFF if you want) and can import audio of various file types for editing. You can record in the background, auto-pause recording when you get a phone call and auto-resume when the call is over, and the app auto-saves while it's recording so you don't lose your session if it crashes or your phone loses power. You can choose from three different sampling rates (8, 22, 44.1 kHz) to adjust the quality (and the resulting file size) of your recording.
The app is a fairly powerful audio editing tool too, and is especially well suited for the iPhone and iPad's touch displays. If you're recording a lecture or a class session, you can highlight areas of the recording that are important or that you want to pay attention to, add tags so you can find important tidbits easily again, or insert typed notes to go along with the recording at specific times. If you need to edit the audio, you can simply tap and select parts of the waveform in the display at the bottom and either snip, trim or delete the sections entirely. When you're finished editing, you can save the final file without overwriting the original (if you choose), upload it to Dropbox, Evernote or Google Drive, or share the file over Wi-Fi to your desktop or another computer.
Recordium is surprisingly powerful for a mobile app, and since it's free until the end of the week, there's no reason not to try it out. If you ever do voice recording with your phone or tablet, or wish you could but didn't have a solid app to use, it's might be a good fit for you.
Recordium (Free) [iTunes App Store]