CSS Library: Horizontal CSS Menus: Here
Uber Round Color Tabs
Author: Dynamic Drive
Uber Round Color Tabs is a solid colored CSS menu with tabs that are well rounded on each side. Thanks to two transparent gifs used to create the corners, the tabs can be customized to any desired color using CSS color values alone. Now that's just handy! Also see DD Color Tabs and DD Color Tabs II.
Two images used (resized for easier download):