Worst case I think we'll know by tomorrow, since it says on u2.com that we should be getting an email with the presale information at some point during the day.
I assume the shows that have the presale this week will go on sale on the 12th, and the shows with the presale next week will go on sale on the 19th.
And I guess at least Portland will be on the first presale since it had the 12th on that ticketmaster page that appeared last week.