I use a home monitoring system that has wireless temperature, water, and door and window sensors, as well as wireless cameras with motion sensors. If anything out of the my specified parameters occurs I get an email sent to my computer and to my cell phone. If there is a break in or a contractor shows up I receive a picture of whoever set off the motion sensor. The down side is that you need to have broadband, but since I do anyway there is no added expense once I purchased the system. The starter kit is only a few hundred dollars and can be purchased at CompUSA. Setup is easy, USB plug and play. You can then buy additional sensors or cameras has your needs require. One thing they lack is the ability to view the cameras real time, but I have other cameras for that. Here is a link for more info.
http://broadband.motorola.com/consum...00/default.asp