I got a new old MacBook the other day and installed Snow Leopard on it as soon as the disk came in the mail this past Friday. It’s weird to be back on a Mac.
Anyway, at some point the procedure for enabling the root account changed. In Snow Leopard, you open Directory Utility in /System/Library/CoreServices. Click the lock, enter an admin password, and Enable Root User in the Edit menu. Enter your root password, click the lock again and you’ve got root.
Apple makes this hard to find on consumer Mac OS X because it’s almost always a bad idea to have your root account enabled. It’s a big security risk. You should be able to do whatever you’re trying to do with sudo.
[via Snow Leopard Tips]