At the moment I am starting samba manually by typing:

[root@Linux-server /root]# /usr/sbin/samba start

What do I need to do to start samba at boot time ?

Many thanks

ln -s /usr/sbin/samba /etc/rc.d/rc3.d/S99samba

you may want to change the number "99" to something else if you want samba to start in a certain order before/after certain other programs, take a look at /etc/rc.d/rc3.d/ to see what the order is on your computer.

Check out:
Getting program to run at boot time.
http://farley.no-ip.org/linux/

Since you are probably running RedHat (from looking at your info), you should have a startup script within the /etc/rc.d/init.d directory called "smb". If not, there should be one on your system someplace when Samba installed. When you put this script into the /etc/rc.d/init.d directory make sure to apply the correct permissions to the file. Also there is a utility on RedHat called "ntsysv" within the /usr/sbin directory. You need to have root privileges in order to execute this program, but it allows you to select which scripts to load at startup. Good luck man! =)

Thanks for your help guys it worked