If you've read any of my more "in depth" articles involving Rooting your phone, changing settings, or flashing custom ROMs and radios, you've heard me reference "adb" (Android Debug Bridge), which is available in the Android SDK (Software Development Kit). The command-line tools are fairly simple, but if you're not performing them all the time they can be hard to remember.
WinADB is a graphical front-end for adb commands which is an all-in-one solution for carrying out the most common adb commands. It even includes USB drivers for most Android devices to make hooking up to your PC that much easier.
WinABD is available from Solo-Dev's page on Deviant Art.
(Via Mike Dopp)