"Open Terminal" is an AppleScript that makes use of the new Toolbar Script system that was introduced with Mac OS X 10.1. It will open up a new terminal window in the current folder. It's also possible to drop files and folders onto the script button. This will open a new terminal session for every item that was dropped.
More information and the download can be found on this page.
[Editor's note: This is a very handy little script - it works as advertised. Make sure you check out Marc's homepage while you're in the neighborhood, too -- he's got some other cool stuff there!]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20011029161835684