I have now translated most of eGroupWare to Norwegian Bokmål.
It submitted to eGW but will not be available until the next version of eGW.
If anyone want to try it, you can download it here:
http://www.speedy.no/egw-no.tar.gzUnpack and copy the egw_no.lang of each module to /usr/share/egroupware/<modulename>/setup/