Crunch: A Simple-Yet-Beautiful LESS Editor & Compiler
If you already use it, then you know that LESS is a "time and byte-saver" when creating + serving stylesheets (if not, you should definitely check it).
You either use the .less files directly (via less.js or on the server with Node.js) or compile them into CSS from command-line and use only the CSS.
Crunch is a free Adobe AIR application that eases the compiling part without the need of command-line but via a user-friendly interface.
It is a simple CSS/LESS editor with syntax highlighting and multi-tab support.