We use software / cameras from Axis (http://www.axis.com/). They do a really good job for IP based cameras and ours is running on Server 2003. Not sure if there is a cost with it since it was installed before I was hired.
Zoneminder is another option out there that I've heard is pretty decent. (http://www.zoneminder.com/downloads.html). If your not familiar with Linux and the setup it appears that they now have a virtual appliance that you can setup. Cost appears to be nothing but time
I found http://www.argussurveillance.com/ Its not that bad to use, has motion trigger recording and such. One thing I don't like about it *besides the 90$ price tag* is the fact it requires you to use IE when remote viewing.
I am going to setup Zoneminder and see how that works out.