Here is another great little utility that adds some functionality that I wish was already built in to Windows. RBTray is a very small (111 KB) GPL/Open Source program that lets you minimize any application to the System Tray by simply right-clicking the applications Minimize button or pressing Windows+T.

RBTray's site is hosted at SourceForge, you can download either the installer version or the binary-only version. Absolutely no configuration is necessary. The source code is also available for anyone who would like to contribute.