Based on a rather cursory examination of the NetZoom product (I use their stencils a lot), they claim to have some significant reporting capabilities. I believe their custom property sets are stored in MS Access runtime images as well. The easiest path would be to just output the reports and then use them as input to whatever mechanism you decide to store them in. One of the advantages is they have done a very good job of selecting a broad spectrum of properties.
There of course are "how to's" for visio (the sdk), vb.net (the vb.net express does not support office, so visual studio but videos are available to teach the basics), database (vb.net examples), and a bunch of others.
Deeper suggestions would pretty much depend on what you are trying to do/what you want to get out of this.
al
