While I was preparing a small presentation on SQL Server centralized management I came across a very elaborate solution on the subject, posted in Codeplex. The solution incorporates three different techniques for gathering, storing and presenting information for a complete environment. The solution is based on Policy Based Management, Management DataWarehouse (Data collection), MAPS tool (Microsoft Assessment and Planning Solution Accelerator) and Report builder for reporting purposes.
The solution provided in Codeplex can be easily modified, expanded and/or rebuild according to the environment specifics but in general it provides you a quick way of implementing a Centralized Management Solution without having to invest in third party tools but use only already installed SQL Servers.
Here is the link to the solution. There is also a very good presentation provided with the .zip file, so enjoy.