Actually in slackware (he said he had 9.1) its done a wee bit different.
the files for apache are in
the two files of importance pertaining to him would be
httpd.conf & mod_php.conf
which should both be there on a default install.
The line at the bottom that i said to uncomment is designated specifically for php by the default conf file in slack.
The mod_php.conf will add php as a module and then setup the MIME types so theres no need for him to add that to his httpd.conf
In essence all he has to do is uncomment the line at the bottom of his httpd.conf relating to php, in Slackware 9.1
Guess i should have been more specific in what i said huh
"generally (in slackware 9.1 with the defaults) navigate to..."