Woa nice link.
Sparkfun is a bit out-of-my-continent though 
I've read on http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1177745205/0#0 that he only got 1200 baud to work. Maybe you just need to try that?
Anyway you are still able to use hw serial
I'll fill this topic up with what i'm doing when i finally get all my hardware delivered.
You can read out my project on http://lamp.allesiskunst.nl/