I bought one each of these:

http://www.dlink.com/products/?sec=0&pid=351

http://www.4netonline.com/ebiz/images/edimax_ip_camera_ic1000.jpg

http://www.hawkingtech.com/products/productlist.php?CatID=33&FamID=14&ProdID=180

The dlink sucks and needs active x to be viewed, and was twice the price.

The other two are both pretty good. I like the edimax best 'cos it's smallest.

All three support activation when something comes into it's field of vision.

All three have the same resolution, which I found wasn't good enough to be able to identify anyone doing something you would want them identified for.

I ended up putting them around the office so I could watch the plotter and printers from home.