For Server 2000/2003 you can use the "System stand-alone Optional
Component Manager" (sysocmgr.exe) to do it.  Basically you just run the
sysocmgr with an answer file and it should do the trick.

sysocmgr /i:%windir%\inf\sysoc.inf /u:c:\PathToAnswerFile.txt /q

Exactly what you want is shown here:
http://thesystemadministrator.com/The_System_Administrator/Tips_&_Tricks/Install
_Windows_Components_from_Command_Line/

For NT4 it's a bit trickier, it doesn't have the sysocmgr.  You have to
install SNMP using the the Network services applet, I don't know how to
install NT4 network services remotely, you will have to do some
searching or someone else can solve that part of the problem.  By
searching through something like this:

http://search.yahoo.com/search;_ylt=A0geu8uMGMtGHmMBdOpXNyoA?p=%22nt+4.0%22%2Bun
attended.txt%2B%22network+services%22&y=Search&fr=

you will probably be able to assemble enough clues to get it done.  Let
us know if you find the NT4 solution.

John