[Sussex] Running command on computer boot

[John Thompson]

Hi all.

When I start the computer the time comes up wrong. Now I know this is 
probably because the battery is going flat - but I am too lazy to open 
the case and too broke to buy a new battery.

I have discovered that if I run the command (in superuser mode):

ntpdate time.nist.gov

- the clock gets correctly set.

Is there any way that I can set things up so that this command 
automatically runs when the computer boots? Even before the user logs 
in? Without having to issue the superuser password?

Well I know it can - I just need someone to tell me how!

Thanks in advance,

John

(Suse 9.3 etc.)