Obviously you have missed the point of the original question,which indicates that I have expressed it badly. iPhone I guess is a bit of a red herring. Let's forget about the iPhone

By embedding a sound file into an html web page, I can create a script which updates a data file elsewhere on the (Apache) server, page is published and the sound file plays automatically.

My question is, if the sound file is accessed directly is there a way that I can register that access and update my data file accordingly?

Um, so you're asking if you can trigger some action based on access? There might be other web server options, but the basic options are to have your cgi program serve the file (but do it smart, Content-Length/Content-Range ...) or you can parse your webserver log files.

If I can invoke the sound file by perl script that would be perfect as I could then make updates to the data file in the same script. Unfortunately I have no idea how to do that, and searching has not helped so far. Parsing the log files would be after the event and I need this to be live (simultaneous).