I gotcha, you are going to use the duemilanove to program the chip and swap it.
For development purposes, you can also pop the chip out of the duemilanove, and make a cable to connect its rx and tx and reset and 5v and gnd to the rbbb versions of the same and serial program the chip on the rbbb directly (they should be right next to each other on the rbbb).
Much more expedient for development purposes once you get it set up. If you are like me, you will have to recompile and upload many many times before you are happy with the software.
Sorry, back to aerodynamics and mechanics...