Rackmonkey
Rackmonkey is a web-based tool for managing racks of equipment such as web servers, video encoders, routers and storage devices. Using a simple interface you can keep track of what's where, which OS it runs, when it was purchased, who it belongs and what it's used for. No more searching for spreadsheets or scribbled notes when you need to find a server: Rackmonkey can quickly find any device and draw a rack diagram of its location. Rackmonkey is free and open source (licensed under the GPL).
The current stable release is Rackmonkey 1.2.5-1.
Status
I worked on Rackmonkey between 2004 and 2009. I am no longer actively developing it.