Some pointers:
First, are they doing this at night? If so, look for something with night vision capabilities.
Second, power source: wireless cameras usually run on a battery, but from what I understand, the battery life is not long at all. It you travel a lot, the usual recommendation is to use the ac adapter that comes with the cameras. This may limit placement of the cameras as you would need to have access to an outlet (some wire fishing may be necessary).
Third, if you travel, you may want to look for something that has web capabilities. Basically, a system that has web capabilities has its own network card installed (or can run on your computer w/software). You can access live video of your house (real time or very close to it) and, if it has a dvr, any motion recordings stored on the drive. You can access this info from any internet connection (you set up a login and password).
Fourth, if you want to catch these clowns, you will need to have footage of them committing the crime and be able to show this footage to the police. Look for something that has dvr capabilites and a high resolution camera to best make out faces, etc.
Some links to get an idea:
http://www.amazon.com/s/ref=bl_sr_el...xtbin=Defender
A little pricey but gives you an example of the aforementioned and actually communicates info/video through power outlets:
http://www.wilife.com/Products/Outdoor-Camera.aspx
Hope this helps