My Mini came with a VGA webcam for which I haven't had any use so far (In case you didn't notice, I'm not one of these twittering, facebooking and flickring social entities. Rather, I'm an antisocial encrypted-IRC type of guy. :D )
In the office, we talked about the use of webcams for security and surveillance, and wondered about available solutions for machines running Linux. I thus came across Motion, a software motion detector. Motion is very easy to use (at the command line), very configurable (with an editor), extensively documented and quite powerful.
For example, if one would plan to use Motion as a security solution, it would be critical that all pictures taken are forwarded in real time to a remote server. That'd be easily done: one would just have to edit ~/.motion/motion.conf:
on_picture_save scp -P xyz %f pdes-net.org:/home/cobra/snapshots/
Instead of xyz you'd have to use the actual port number, of course. ;)
Here's an example of Motion in action. It detected my cat en route to the bedroom. ;)
Some options I've used when taking this image were mentioned in Chris Page's blog.