Command Line parsing

Hi
I'm trying to parse through the command-line parameters of one of my scripts.
Basically I want to perform an operation on $1 and then the same operation on
$2 and $3 and $4, until there are no more parameters.

I don't know how I'd increment the <position number> of $<position number> but
that's what I'm trying to do... I have no clue how to do it cleanly and simply
using sh... is there a way in csh?