MACMEDIX  Eavesdrop is really great for what it does!

If you've forgotten your email or FTP password, but it is saved as a FTP bookmark, you can use Eavesdrop to listen in on the conversation between your FTP software and the server. Since the pw is often sent in the clear, you will be able to see it as it goes by.

Just one of the useful things you can do with Eavesdrop.

Works fine with Tiger, Leopard, and maybe more OS X versions.   
(Version 0.5a4)

MACMEDIX  Great, simple command line utility to view what the isight cam sees. This WILL turn on the camera's indicator light while the photo is being taken (about 3 seconds). Works fine in Leopard OS X 10.5.3. Saves photo file to same place as the application is unless otherwise specified. application file can be anywhere, doesn't have to be in Apps folder.

Good excuse to learn scp so you can retrieve the photo file. I heard of this from the comments under the story about the recovered stolen laptop:

http://community.livejournal.com/macosx/5713803.html  
(Version 1.1)

MACMEDIX  Great for sending occasional faxes! Keeps a log, and uses Mac Address book. We send about 10 faxes a day via another Mac running PageSender with Printer Sharing on (and a fax phone line) to make a network fax server. It works, but gets jammed up several times a week. Sometimes requires a delete & remaking of the printer spooler (both ends), or Mac OS restart... Not consistent in that regard. Not great as a fax server.

Works great for individual, occasional use, even works great for occasional network use.   
(Version 4.1.1)