How can I capture an audio stream?

If you're a Mac user, the simplest way to achieve this would be to use the original, free version of WireTap. Unfortunately, version 1.0 is no longer available from the official home page (oh look, they have a pro version for sale - could the two things be connected?), but can be found elsewhere on the web if you're prepared to scout around for it.

WireTap is an atypical stream-ripping tool in that it records any sounds emitted by your Mac within a given time-frame - it doesn't discriminate between applications - it will pick up system beeps, iTunes output, everything, so if you require a 'clean' recording, ensure that you mute the sound in all applications bar the target source before you begin 'tapping'.

The interface consists of three buttons - record, stop and pause. To save an audio stream you would click on the relevant link in your web browser to commence playback and then hit the record button in WireTap - the captured sound is saved to a folder of your choice as an AIFF file. If you wish to save streams in MP3 format you will have to upgrade to the pro version or use Audio Hijack instead. Incidentally, Audio Hijack will allow you to capture audio from specific applications, and additionally grants you much more control over the quality and format of captured sound files.

The handful of PC users amongst us *wink* might like to try Stream Ripper instead. This being a more traditional stream capturing tool, it records audio streams directly, ignoring any extraneous background system noise. It can't interpret Windows Media or Real Audio streams, but pretty much anything else is fair game.