In order to tell which databases your SharePoint 2007 / WSS 3.0 installation uses, you will have to look at multiple locations.
Content databases
Open Central Administration and go to Application Management and then Content databases
Review for all Site Collection URLs
Shared Services Databases
Open Central Administration, Application Management, Manage this Farm’s Shared Services
There you will find
SSP Database
and
Search Database
Configuration database
Look in the registry at:
HKLM\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\12.0\Secure\ConfigDB