Ok, I had this problem too, but I fixed it.
You probably had apache already setup on your linux machine, and by installing apache_1.3.12 you're installing a second apache (lemme guess, you put it in /usr/local/apache with the --prefix=)?
Anyway, you would now have to apache servers running, both binding to the same port. Even though they probably both point to different document roots (/home/httpd/html and /usr/local/apache/htdocs). Even if you chmod a+r (index.html) so that you have access to view it, if you have 2 apaches running on the same port you won't get anything.
What you want to do is go into the original apache (which you probably isn't setup with your php4/mysql). This is usually located in /etc/httpd, go into conf and cp httpd.conf to httpd_tmp.conf, and then remove httpd.conf, this will prevent the old apache from starting during reboot. Reboot, httpd will fail. Now you go into /usr/local/apache or wherver you installed the new apache, go into the bin directory ./apachectl start or ./httpd This will fix your problem. Don't forget to chmod a+r index.html in your htdocs directory either.
For a very good tutorial on the whole apache_1.3.12, php-4.0.0, and mysql goto http://www.devshed.com and check out their tutorials (they also include openssh and mod_ssl in their tutorial). Remember, you can always ./configure and remake if things don't work.
