MS SQL 2005 Management Studio
When using a database that is unfamiliar to you try to create “Database Diagrams” in order to visualize the relationships between tables, as well as the tables and it's variables.
To do this, open the correspondent data base, right click on the data base name and chose the “Database Diagrams”. Right click on it and chose “New Database Diagram”. Select all the tables on your database and create a diagram, the Management Studio will automatically distribute the tables in a way that the relationships between them will appear.