The default name of a database can be set when the database is created, or
modified by the ssadmin utility by its Tools, Options menu, General tab.
However, you can set the name of a database to whatever you want (overriding
the default) when you add it to your list of databases.  You can either
remove and re-add the database, giving it the name you want, or edit the
registry.  The names of your databases are stored in:

HKEY_CURRENT_USER\Software\Microsoft\SourceSafe\Databases

-Mark