This is something I've been looking into a little bit (basically started tonight) and so far I have found 3 things that may be similar to what you are looking for.

Cisco's Network Magic
SpiceWorks has a free program that seems to be add supported
and SingleClick's HomeNet Manager

None of them quite seem to match what I'm looking for so I plan to keep looking, though SpiceWorks seems close enough to seriously consider it. Googleing the term 'Home network management software' seems to yield the kind of results we're both looking for. Happy hunting & good luck.