SVG Gradient Background Maker
Handy
The ultimate CSS tools for web designers | CSSmatic
Gradient generator, border radius, noise and box shadow
Creating Single Element iPhone using CSS3 | CSSDeck
On the amazing use of box-shadow
Create Columns Easily With The CSS3 Multi-Column Layout Module
Adactio: Journal—Sea change
Responsive design
10 tips for designing mobile websites | These Days Labs
Webkit CSS Properties
Safari for Desktop and iPhone properties listed in a table. A must have.
CSS Border Radius
Try out border radius and copy/paste css
CSS3 Please! The Cross-Browser CSS3 Rule Generator
You can edit the underlined values in this css file but don't worry about making sure the corresponding values match, that's all done automagically for you.