Less-autocompiler is a project mainly written in Java, it's free.
A wrapper around the less compiler for Windows, to make it easier to watch less files and compile on the fly
A wrapper (written in Java) for the less compiler, to be used on Windows, because those poor souls don't have the wonderful less app we do on Mac.
As it is a wrapper, you NEED a working lessc compiler on your machine. For Windows, take a look at http://blog.dotsmart.net/2010/11/26/running-the-less-js-command-line-compiler-on-windows/. There is a zip file there you can extract in your system32 folder (or wherever your PATH is looking) to use it.