Hi!
The old wikiCalc screencast, although a little out of date now, is a
good introduction: http://www.peapodcast.com/sgi/wikicalc97demo/
As for installation, it's usually just a matter of downloading,
unpacking, and then running bin/socialcalc.pl (or bin/socialcalcwin.pl
under Windows). This version uses a built in mini-webserver that has you
up and running straight away on your local machine.
You can also use bin/socialcalccgi.pl to run the server based version
(or bin/socialcalcmodperl.pl under mod_perl).
Let us know if you have any difficulties and questions.
Thanks,
Tony