I've never had a problem buying U2 tickets over the years, even on the Vertigo Tour. Got GAs for all 14 shows I saw in 2005-06, either from buying them online when they went on sale, or through trades. I wasn't even a member of U2.com, because I knew they would release crap tickets during their presale, like most bands do.
Tickets for the Oakland and Portland shows were easy to get, I don't think any of them sold out until the final few days. San Jose was tough, but I got lucky and logged in at the right time to get GAs for both shows. I traded a Boston GA for the two Las Vegas show GAs. Hawaii GA was easy. Learned some Spanish and bought GAs for the three Mexico shows on
http://www.ticketmaster.com.mx.
Bought all three Tokyo GAs online after dogging the Japanese ticketing agency with endless emails inquiring about how to go about purchasing tickets from the US. I think only one of the three Tokyo shows was sold out. People were dumping tickets for pennies on the dollar outside the venue at Tokyo 3. Same deal in Glendale, AZ, I heard. A friend of mine bought a GA for the great Glendale 2 show for $10 out front.
U2 2009 will be similar, I suspect. The economy will still be bad, so I don't think they'll be able to raise ticket prices to Madonna/Stones levels. I've signed up with U2.com this time, because I plan to see U2 in Boston and New York, which are tougher tickets. I'm thinking about a trek to Germany/Italy/Holland/Ireland/East Europe to seem them, but stadium show tickets are usually pretty easy to get, though maybe not in Dublin.
I'm not worried about Live Nation managing U2's ticket sales. They're already selling tickets for big tours without any issues:
http://www.livenation.com/artist/getArtist/artistId/14934/
The best thing to do is make friends with U2 fans all over the world, and work out a reliable ticket-trading system with them, if you can. For example, I've already arranged to take care of U2 fans from Japan, Australia, Mexico, Los Angeles and San Diego when they come over for the Bay Area shows, with the promise that they'll take care of my ticket needs if I fly out to their neck of the woods. I need to work on my European and East Coast contacts next, I guess!
(Hey pepokiss, promise to get me into U2 Santiago GA next time, and I'll handle your Oakland/San Jose, CA tickets if you decide to come up here)