I want to have a remote wireless camera about 100 yards from my PC to record the animal that's occasionally getting into my hen house and just killing a chook and leaving it there. It only happens at night so I'll need a camera to suit. All help appreciated.

You can try your local hunting store. They have cameras you can set up and set the sensetivity for. Then download it onto your computer. It would be easier then trying to get a connection at 300 ft. Also cheaper on batteries too.

Are you set on a Network camera, or receive Video and input to Computer.
This place has some nice gear at good prices:Personal Protection Video Security Camera Systems (http://www.supercircuits.com/personal-cctv-products).
Optex make some good long rang portable wireless motions:
http://www.optexamerica.com/productpage.aspx?l1=2&l2=&id=38
They are good to 1000', I love them, I use when camping in remote areas.
Your camera will need IR Illuminator as well, to see in the dark.

I think this is what calidadof3 was talking about:
http://www.amazon.com/Stealth-Rogue-IDVR-Infrared-Emitters/dp/B001SG92I6

Thanks Guys. I'll keep your info on hand when I get further with the project.