How to determine which databases SharePoint uses

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