I am trying to replace my Rheem thermostat with a new Honeywell RTH 230B. I have 6 wires coming off my Rheem, what I am trying to find out is how to wire up my new one.

Is your new thermostat for a heat pump?

Here is a copy of the manual with all the instructions. Just follow them.

http://customer.honeywell.com/techli.../69-1900EF.pdf

Yes it is, heater/ac unit, single stage.