I used cameras from x10.com and they worked quite well and were very affordable at about $100 a piece. You can setup 'internet' viewing to checkin remotely. The 'ninja' based cameras allow the camera angle to be moved remotely too. And you can record to a VCR if you want to. I had a monitor setup in my bedroom so I could check on Mom without disturbing her, and with the night cams, it was easy to do so.
Sam's club sells cameras. We have several set up around the house and I can get online at anytime and see what is going on. This cost us about 1800.00. If that is out of your budget, do a search for Nanny cams or call Radio Shack. They have those small cameras that are okay and motion activated for under 200.00. Hope this helps.
Carol