(some components can be made to be cheaper)

Rasberry Pi http://amzn.com/B009SQQF9C $38

camera http://www.newegg.com/Product/Product.aspx?Item=N82E16813995017 $30

Poe adapters http://elabualg.wordpress.com/2012/02/06/power-over-ethernet-poe-adapter/ $10

cover/case http://amzn.com/B004CBGFOS $25

+misc parts

I can't seem to find a decent wired network camera that is high def.  The foscam is close, but more expensive than the setup I propose. 

Http access allows any device with a web browser to view and capture.

OS and config here

http://www.raspberrypi.org/camera

http://www.instructables.com/id/Raspberry-Pi-as-low-cost-HD-surveillance-camera/?ALLSTEPS

http://www.maketecheasier.com/raspberry-pi-as-surveillance-camera/

http://www.stuffaboutcode.com/2012/06/raspberry-pi-run-program-at-start-up.html