Schnapple asks:
Are you referring to the concept of a
free database to distribute with an
application, or an Access-like "single
file, no installation" database?
Er, nobody who has any competence with Access application development would ever distribute a single MDB/ACCDB as application/data store. Any non-trivial Access application needs to be split into a front end with the forms/queries/reports (i.e., UI objects) and a back end (data tables only).
It's clear that what is needed here is a database application development tool like Access. None of the database-only answers are in any way responsive to that.
Please learn about Access before answering Access questions:
Access is a database application
development tool that ships with a
default database engine called Jet.
But an Access application can be
built to work with data in almost
any back end database, as long as
there's an ISAM, or an ODBC or OLEDB
driver for that database engine.
Microsoft itself has done a good job of obfuscating the difference between Access (development tool) and Jet (database engine), so it's not surprising that many people don't recognize the difference. But developers ought to use precise language, and when you mean the database engine, use "Jet", and when you mean the front-end development platform, use "Access".