configuring service autostart option

This could be done using chkconfig program

To check the service startup option in different runlevels (i.e. mysqld):
chkconfig | grep mysqld

to enable a service in all runlevels
chkconfig mysql on

to enable a service in specific runlevel
chkconfig --level 3 mysqld on
To add a new service:
chkconfig --add mysqld

Linux RunLevels:

0 - System halt; no activity, the system can be safely powered down. 
1 - Single user; rarely used. 
2 - Multiple users, no NFS (network filesystem); also used rarely. 
3 - Multiple users, command line (i.e., all-text mode) interface; the standard runlevel for most Linux-based server hardware. 
4 - User-definable 
5 - Multiple users, GUI (graphical user interface); the standard runlevel for most Linux-based desktop systems. 
6 - Reboot; used when restarting the system.