U2.com has updated the information on the Tour Info section and it looks pretty clear that the new system will only be for people who didn't get tickets in this 1st let:
"Presales for U2.Com Subscribers for the Vertigo//2005 Tour are now - with the exception of Portugal - just about over..
Thanks to everyone who took part.
Most Subscribers have been successful in securing tickets for the North American and European dates announced so far.
But we had some problems, particularly on the North American leg, and some Subscribers have not been able to get tickets for the dates announced so far.
As Larry explained in an open letter to fans, the band are now making plans for a return to North America in the fall.
With this in mind, we are working out a new presale ticketing system aimed at prioritising long-time Propaganda members who joined U2.Com and have yet to get tickets and at other U2.Com Subscribers who have yet to get tickets - based on when they joined."