BCM 2007 uses SQL Express 2005. The instance name should be named or similar
to MSSMLBIZ.
For the exact location of these files, this information is helpful.
If you are using Outlook Business Contact Manager and wonder where the local
database is stored on your machine look no further than here in Windows XP:
C:\Documents and Settings\{username}\Local Settings\Application
Data\Microsoft\Business Contact Manager
Should be a .ldf and an .mdf file for the database that looks similar to
this:
{DatabaseName}OutlookDefaultProfile_offline
taken from http://officepoint.blogspot.com