Snippets - Is there a db that tells what snippets do?

They are stored as XML and if remeber correctly you can set local snippets in your vs05 profile or via the TFS (Not sure about the TFS) and you can also add the description for the snippet.
Forgot to add, there is also a snippet manager in the IDE Tools -> Code snippet manager. So you can add say from your network or even search online for snippets.

Hope that helps

Team Foundation Server. Snippets are more of a VS 2005 IDE feature rather than a TFS feature. I'm pretty sure they are not part of the TFS db structure.