I'd like to wire a few phones together to use a intercom. Any body have any ideas as to a good starting point.
A good starting point would be Google :)
It's not overly difficult to do assuming you don't need the phones to ring. You just need a power source which depends on the length of the cable runs and number of phones. You can build a small system with a 9V battery even.
If you need the phones to ring it's a bit more difficult as you need to apply 90V A/C at 20hz (I think).
Seriously though, Google it, you will find many walkthroughs and instructions on how to build these.