Last I heard, they are still awaiting final certifcate approval from the FAA. POI indicated to a fellow crew memeber that might occur in February 2007. 36 EMB-175s are supposedly on order for the operation with deliveries starting at some undisclosed time in 2007.
Seeing as how it is NWA, none of the above may be true and it is a certainty that it is subject to change.