Two sites that could help you out.
Magnatune.com Lots of popular music that can be licensed for anything. They don’t have U2 but they do have some really good musicians.
Garageband.com Is a site highlighting independent musicians. They don’t handle licensing, but each artist has a button to contact them directly so you can talk to them about getting rights to use their music.(good luck calling Bono directly) Also each band is catagorized by who they sound like…perfect if you need a “sound-alike” track.
check em out.
J