How to do a proper scripted administrative installation?

[Entity]

I'm trying to install a few apps (all by Microsoft) onto several computers; I know that you can run a type of setup so that when you setup initially, you can keep all the settings constant and script them to a file. How do you do this? Running setup /a right now puts me in administrative setup, but I don't know what to do from there.

To summarize: I want to do batch installs of MS products, and want to know the commandline to do so. I know that once you have a script file for an installation, you can model the other installs after that...

Thanks.

Rob