Flash Log-in, customer data base, suggestions?

I've taken over a flash site. I need to enable a log-in, registration page that collects the standard customer date somewhere.

I'm a fair coder at best.

I was wondering if anyone had a suggestion for a tutorial.

Or a suggestion for the type of database we might want to use.

Can we use XML to produce a tab delineated file until we can set up something more substantial?

I'm not going to get through this without the help of the good people here and I desperately need the job.

Many thanks.