I worked on a flash project that did something similar to what you want to do. I wasn't the programmer but I know he used php to achieve the client database communication. The game takes part "live" and we were able to create a turnbased system within teams of players by synching them on start up. You can see how far we got on http://klimaxgame.nl, click on work in progress version. If you need help I could ask the programmer if he doesn't mind giving his email to you.

cartoon_baboon