"CSSTidy is an opensource CSS parser and optimiser. It is available as executeable file (available for Windows, Linux and OSX) which can be controlled per command line and as PHP script (both with almost the same functionality)."
While a lot of people are out to optimize their sites/blogs, most everyone seems to skip over CSS. I have been spending some time looking at CSS Optimization tools today. I wanted something free, online, and easy to use. And of course, something that worked.