I haven't seen this in any of the other threads, so I apologize if this is redundant.
http://www.indoor.flyer.co.uk/probe.htm
This guy made a DIY probe for his mill.
I also saw a link to a web-cam mount for a CNC mill, but I can't find it right now. I'll update this thread as soon as I can find it.
Gerry
Mach3 2010 Screenset
http://home.comcast.net/~cncwoodworker/2010.html
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)