Service startup settings

Hi,

I have 5500 NT 4 Wkstns all with a particular service running on them. Due to staff changes we need to change the startup settings of this service. It uses a local admin. account to log on as a service to do its work.
I want to change the service account password. This is not too difficult, net user username newpassword, will do the job. But I also want to change to the new password in the service properties. Due to the number of machines in question I would rather find a way of doing this remotely/automatically/without user intervention etc.,
I have a software delivery product, TNG, that will let me run jobs on all of my machines.

Any help, suggestions, ideas etc., will be gratefully received.

Pat