Skybound Stylizer is a CSS editing program that I have been using for many years now and it is a great peice of software. It has the ability to perform on the fly CSS file adjustments either point and click or type code and has multiple browser rendering built in. At current time is supports multiple versions of Internet Explorer, Firefox and Google Chrome.
This program is very easy to use and offers the ability of working local or directly on your server. Once finished with your css adjustments, you can either save local or to your server. Many of the adjustments can be made with sliders and you also always have the option of manually typing in your values. Skybound keeps it updated and does so from within the program.
I definatelly rank this as the BEST CSS EDITOR on the market today.
Visit them and have a look for your self - they offer a free download.