Adding PHP, forums, and html to flash?

In a flash application, can you stilll apply forms, etc. with PHP? Can you apply phpBB (I'm assuming you can if they former is true). Can you add just regular html? Or is using flash limited to just using the tools in flash?

forms yes. forums (like php/html based) no. HTML is not rendered in Flash (with the execption of a few formatting tags). Although you can create a BB in flash and script the backend in php or something. you could find an example of that here:
http://www.phpforflash.com/

Huh? If you can't do php, how can you do forms?

you can send variables from flash to a php script and run it
that way. go to http://www.unflux.com and check out my contact
section. That form actually emails me via php.