are you unable to see apache at all, or just the php app on apache?
are you trying to access this form the machine it apache is running on, or a network machine?
If you are accessing it locally, does
http://localhost do anything for you?
If you accessing it from another machine, is there a firewall in the way?
Is the php application placed in a directory that apache can see?
does apache have permissions to use the php application files?