Clustering using VMWare images - how??

Hi
I would like to understand the basics, setup of a cluster. I have a
powerful machine in i7, 6 gb ddr3 Ram. I was thinking why not clone a
same ubuntu vmware image as 4-5 ones, start them up together and work
as a cluster. But my thoughts couldn't be converted as actions as I
don' t know anything about clustering, how to make 1 system know the
other, how to attach static IP, or what cluster software is free/
easiest to maintain.

I am thinking of installing multi-partitioned database server in
either DB2 or Oracle and use 1 other system in my home network as
application server and want to play around.

Please link me to any articles/cluster software that are free/easy,
and how to make 1 system know the other 1? meaning how to even mount 1
vmware image in another etc.

Thanks
Arun