Have you looked at MS "System Management Server" ? It's supposed to be able to do all this "inventorying":

Microsoft® Systems Management Server 2.0 includes detailed hardware inventory, software inventory and metering, software distribution and installation, and remote troubleshooting tools. These integrated features make Systems Management Server 2.0 the most scalable way to reduce the cost of change and configuration management for Windows® based desktop and server systems. Systems Management Server 2.0 is built on industry-standard management protocols, ensuring compatibility with complementary management tools. Systems Management Server 2.0 is tightly integrated with Microsoft SQL Server™ and Microsoft Windows NT® Server operating system, making it easier than ever to install, configure, and maintain Systems Management Server in any size network.


http://www.microsoft.com/smsmgmt/default.asp

Full Version Media: CD
$1,129.00
Microsoft® Systems Management Server 10 Client


>Hi Everyone!
>
>I need some major help on this one. My boss has given me the task of remotely auditing our local network workstations. I've designed a small app in vb that would audit the machine I installed it on about 2 years back. Unfortunately though, I have no idea how to get the info from a remote machine via ip to my workstation, or one of our servers.
>
>We looked at other of the shelf packages, but nothing really worked for our limited IT budget, or would integrate with our existing inventory system.
>
>This is really bothering me. I'm a mid-level programmer, not an expert. So please, any help you can send my way will be greatly appreciated.
>
>Thanks,
>
>Doug Phillips
>Birmingham, AL