I've recently made available a little project of mine called LoopCenter.  It is a live-looping tool with a functionality very similar to the Boss LoopStation pedal.  I use it mainly as a improvisation practice tool, but it could certainly be used for more compositionally-oriented stuff.  
<br><br>Basically, you can set a tempo, and easily record and overdub small, measurized segments of audio, and then loop them.&nbsp; It is similar to SooperLooper (an excellent piece of software that I found only after making LoopCenter!), but pared-down, and perhaps easier to use.&nbsp; It runs with JACK.
<br><br>Check it out at:<br><a href="http://loopcenter.sourceforge.net">http://loopcenter.sourceforge.net</a><br><br>Thanks!<br>-Nick Choly<br><br><br>