you can choose which services to start at boot and which not to start by either taking the executable flag of the appropriate script in /etc/rc.d/ away, in which case the dont start automaticaly, or set the executable flag.
you want apache to start at boot:
`chmod a+x /etc/rc.d/rc.httpd`
you want apache _not_ to start at boot:
`chmod a-x /etc/rc.d/rc.httpd`
(theese commands have to be issued as root )
to stop a deamon, i.e. apache at runtime:
and to restart