in users/root? well, locate passwd from your own account, copy the gibberish there is (your password encrypted) and locate passwd for root, and paste the gibberish replacing the old gibberish there is...or better yet: read this thread: http://www.macosx.com/forums/showthread.php?s=&threadid=10965
and for more info on regaining control over root: http://www.securemac.com/macosxsingleuser.php
(I followed latters directions when I forgot the root password...)
or better yet you can just pop in your mac OS X install CD and when the installler starts there is an option to change the password without having to reinstall.