Sort of. By Irish standards. There's this interview with BeliefNet. There was mention back in the late Eighties that most of U2 were members of a Christian fellowship of some sort which sounded evangelical.
This article talks about that group, Shalom, and has a quote from Bono that he is sort-of-maybe Catholic, at least to the extent of raising his kids "technically" as Catholics. There's a chunk here that describes Shalom as charismatic & non-hierarchial, which definitely matches my informal definition of "evangelical".
This article seems rather definitive, though. They left Shalom in the Eighties over the whole rock-star thing, but are still pretty much believers in that tradition, just unchurched.