You can get the url of the swf (and extract parts of it using
String methods) but not of the html page within which its embedded
(unless you pass it to flash as a flash var - e.g. in the static
html... or more likely, from a server side script that generates
the page content).
The url is accessible via the ._url property of the MovieClip
class, you can use
to access the url of the swf on the main timeline (as2 code)