1. Introduction to CSS3
This is a great introduction on same basic new additions that CSS3 add to the style sheets.
2. Gradient Generator
You can pick the colors and customize the gradient and this site will generate the css for you.
3. Gradient Buttons Tutorial
This tutorial is quite detail explaining the versatility and implementation of these buttons.
This is a great tool and style element that can be a very subtle and nice touch to websites.
This one can be really badly done, but also another excellent subtle touch as well!
6. Opacity and Transparency
7. Minimalistic Navigation
Great resource for a lot of freebies here.
8. Beautiful CSS3 Search Form
This is a great example of what can be done with the new CSS3 additions on a small level.