Block User-agents via PHP. Very handy in keeping out unwanted e-mail harvesting programs, programs that copy websites, etc. When a defined agent attempts to access a protected page, it will return a custom error message built within the script. It also sends an e-mail to an address you specify, detailing the attempted access.
Similar to above, except in Perlflavor, and returns a custom URL instead of a built-in message.
Same as above, except in ASPflavor.
Simple username / password protection script. User enters a username / password in a form, and gets either redirected to the secure area or denied if the username or password is incorrect.