Before anything else, it's a preview, so it may burn you. You've been warned!
Surprise, surprise! I hope you didn't see that one coming. I've had a hard time keeping the secret...
Every color that you may desire. By moving a humble slider that rotates the color wheel. Simple as that. And if you don't know what you're looking for, there's a "surprise me!" "randomize" button, just to make your life easier.
If the colorization was not enough, or you want some elements changed, you can do so for the Grid, PanelBar and Window controls. We'll be adding more controls at a regular basis, that's a promise! Hopefully, all controls should be added for the Q2.2009 release.
Just a note about editing the box model:
The interface is the same as in Firebug - margins/borders/padding can be edited by clicking on the numbers and editing the value (as in the screenshot). Editing border color is done through clicking on the border (the black/orange part) and selecting the color through the color picker.
You'll need IE7+ or Firefox 3. Exported skins will work with IE6 - it simply does not support the editing. Chrome has some weird issues with the fine-tuning interface, and they will to be resolved soon.
Silverlight 2.0 is required for the colorization interface, importing skins or uploading background images.
You know the drill! It's beta - therefore, there are no support tickets; forums are always open for discussion, and of course, blog comments are welcome! Also, tag your tweets with #vsb ;-)