I'm using CB 1.2 RC3 on a new site and have an existing site which I'm about to close down which is running CB 1.2 RC2. Both sites are running Joomla 1.5.

How do I migrate my CB users from one site to the other to avoid them having to register on the new site. If I need to use phpmyadmin to run queries on the database I know how it works but I'm not very experienced so if someone could give me a step by step guide that would be great.

My challenge is even more generic. I have to migrate users from a proprietary database to CB.

1 ) Any suggestion in terms of which tools to use?
1a) Is there possibly a generic matching tool for mySQL databases to match old structure of a database with the new structure (CB structure) available?
1b) Is there possibly a script to upload a predefined table (CSV-file) representing the user data into the CB database?
2) How is a CB user represented in the CB database (field and table names)

This must have been done before many times ...
No?

Any comment even of the most general kind is appreciated.
Thank you!