Sharing the load over 2 linodes

Hi, hope I'm posting this in the correct place, if not sorry and please feel free to move it.

What I want to do is this..

run mysql, and a mail server etc. on one linode, and host my sites and a few other things on the other.

I'm just having problems working out how to setup the private IP's so my linodes can speak to one another.

Can anyone give me a step-by-step on how to go about setting this up please.

Kind regards,

Nick - KBcdn