[via Angus]
James Milne has create a nice website interactivly create a skin for a SPS 2003 website.
Abstract
The SPSkin Designer can be used to quickly and easily create style sheets (CSS) for SharePoint Portal Server and Team Sites. The Designer provides a GUI interface to modify the look and feel of SharePoint. Once a Style has been developed you can copy the style sheet and apply it to your Team Site or Portal. Version 2.0 has the following new features: Addition of 200+ exciting Styles Addition of a ColourPicker