Different boards

There are loads of different types arduino boards but is the code the same for all boards. :-? I have some freeduino maxserial code and wanted to use it on a duemilanove. would i have to convert it or get some more ?? :-/

All but some third party boards support the main arduino code.

Freeduino, Seeeduino, Arduino varients [Mega, 2009 etc], Roboduino... All mutually compatible..