Good news for you. Both United and USAirways have indicated that they will accept WorldPerks award tickets without any sort of endorsement from NW. Northwest Airlines has restricted both UA and US to booking NW passengers out 3 days. So, if you are going somewhere for more than 3 days, you will have to worry about your return once you get to your destination.

Also, this is very important...go to your NW city ticket office, travel agent and get any E-tickets converted into a paper ticket. If you do not convert to a paper ticket, you will need to wait in line with the masses at the NW counter in the airport to have it converted to paper anyway.