Hey, i love full flash sites myself. Not because HTML is boring(it can be just as good[better], it just takes the right amount of experience and work) but because of the flexibility.
I've done what you want to do. Basically you'd have to use PHP(or another server-side language) and the loadvars function in flash(or its newer relatives). It would be worthless me re-iterating what i've learned here when i can direct you to where i learned it from...
Go To And Learn is a brilliant free video flash tutes site. The one you want to look at is entitled "PHP, MySQL and Flash"... I also advise you take a look around the rest of the tutorials if you get a spare moment because they are brilliant.
Cheers,
Jamey