wss

Start -> All Programs -> Control Panel -> System
On the Advanced tab, click the Environment Variables button.
Select the variable Path and click the Edit button.
Add the following to the end of the Variable value field (don't forget the semicolon... the Path environment variable is a semicolon delimited string of directories):;C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN
OK out of all the dialogs.
Next time your system restarts, you'll be able to type STSADM.EXE at a command prompt from any directory on your system.