SQLDependencyViewer is a handy tool from Red-Gate that shows the dependencies between objects in your database. A dependency diagram is produced that gives a view on how the objects in your database are interlinked. One feature i really like is, when you click on an object in the generated diagram it shows the objects depending on it and objects it depends on in different colours making it very easier to comprehend.
Filtering and selecting objects and saving the generated images are a few features that will make it more useful but nevertheless it is a good tool to have and it is free. Check it out at the following URL