How to run a script at startup

[Richard Stanton]

I downloaded that netatalk package using yum onto my ydl 3 setup.  As
part of this an 'atalk' script was placed into my /etc/init.d directory
- however after a reboot the atalkd & afpd daemons aren't running. 
Running the atalk script manually from the init.rd directory results in
them starting correctly, so I know the script works.  How do I ensure
this script is actually run during boot?