All I know is what the words know, and dead things, and that makes a handsome little sum, with a beginning and a middle and an end, as in the well-built phrase and the long sonata of the dead. -- Samuel Beckett
I've now uploaded the script I use (in conjunction with FireHOL) which helps to stop script kiddies from continually attempting to login to my machine as root, and what have you.
Nothing too fancy, every 15 minutes it scans /var/log/auth and acts on it: if some one tries to logging as root or some other invalid user they get blocked. It allows a few failed attempts for real users just in case - this only applies to passwords, not usernames!