Can't access web pages: Access forbidden!

[sliemm]

Hi guys
I've installed Xampp on my mac and am trying to access my index.php files in my folder within the htdocs folder (I put localhost/xxx into the URL field), but I get this message:

Access forbidden!

You don't have permission to access the requested object. It is either read-protected or not readable by the server.

If you think this is a server error, please contact the webmaster.

I've searched all over the web for a solution, and all I can find is that I need to change permissions in my httpd-xampp.conf file, but this file is locked - I can't edit it at all.

Can someone let me know a) how to unlock and edit this file, and b) exactly how to change permissions so I can view my web pages?

Thanks.