Here you are: http://cssrefresh.frebsite.nl/
CSSrefresh is a small, unobstructive javascript file that monitors the CSS-files included in your webpage. As soon as you save a CSS-file, the changes are directly implemented, without having to refresh your browser.
Just insert the javascript file and it works!
But note: It only works when you have the files on a server!
Edit: LiveStyle
If you develop with Sublime Text and Google Chrome or Apple Safari, then you should use Emmet LiveStyle. This is a more powerful Live CSS-Reloader.
Now I use it instead of CSS Refresh.
If you want more information about this awesome plugin, please read the Post by Smashing Magazine