The most straight forward way would be to use the FlashVars parameter. It is defined via an HTML param tag like this:
<param name='flashvars' value='name=value&name2=value2' />
The value must be formatted as a URL query string. The indiviual key/value pairs will be made available in the root of the SWF movie. In AS2 you can simply access them using _root:
_root.name
_root.name2
In AS3 these values are available via LoaderInfo.parameters:
root.loaderInfo.parameters.name
root.loaderInfo.parameters.name2
Long story short, you could do it like this in PHP:
<param name='flashvars' value='fname=<?php echo urlencode($_GET['fname']); ?>' />
and then in AS:
fnameurl.text = _root.fname;
// or
fnameurl.text = root.loaderInfo.parameters.fname;