SQL Server: Data dictionary
Data dictionary creator  is a simple-to-use free tool that helped me immensely with a SQL Server database documentation. It stores all the information in Extended Properties, so it’s easier to keep the documentation in sync with the database as it changes. I was able to generate a data dictionary with a couple of of mouse clicks after I have entered the connection string. The dictionary can be exported to various formats: Excel, XML, Word and HTML. Click on the reference  for a step by step tutorial on the usage of this utility. (The current version does not seem to support SQL Server 2008). This can be download from codeplex.
1. Data Dictionary Creator