It's not quite the same idea, but WebPutty (www.webputty.net) targets a similar problem and works cross-platform (it's a web app).
WebPutty is a free CSS editing and hosting service that gives you a syntax-highlighting CSS editor, supports SCSS and Compass, and provides a side-by-side preview pane that's updated as you make changes to your CSS. It also enables instant publishing with minification, compression, and automatic cache control (if you chose to host your CSS with WebPutty).
Full disclosure: I'm one of WebPutty's developers.
WebPutty is a free CSS editing and hosting service that gives you a syntax-highlighting CSS editor, supports SCSS and Compass, and provides a side-by-side preview pane that's updated as you make changes to your CSS. It also enables instant publishing with minification, compression, and automatic cache control (if you chose to host your CSS with WebPutty).
Full disclosure: I'm one of WebPutty's developers.