_yak technoblog

For building Swing based application one might seriously have a look at the mature JGoodies libraries

JGoodies Bindings – for leveraging MVC based SW design by loose coupling domain logic such as jabva beans to Swing gui components
JGoodies Looks – with this library the Swing gui will also look good
JGoodies Forms – definite way to go to avoid Swings dull layout managers and easy and consistently place JComponents in a GUI window

http://www.jgoodies.com/articles/

[Edit]
Other projects that also features enhanced GUI elements and look and feel is listet here
http://www.tutego.com/java/additional-java-swing-components.htm