I Heard that With or With out you was pretty good for beginners? I believe in a video I found recently Edge said " this is one of the easiest U2 songs to play". But I'm not sure, I'm just learning. I only know a couple chords right now, C, D, Em, G, and I believe Am.
acoustically and just on a rhythm basis, WOWY is fairly simple.
D, A, Bm, G
Another somewhat easy one is All I Want is You.
A, D for the verses
F#m, D for the prechorus, "all the promises you make from the cradle to the grave.."
A, D for the chorus, "when all I want is you"
A, D
really, if you break down a lot of U2 songs and take away the effects and just go to an acoustic rhythm, they're fairly simple, even a song like Where The Streets Have No Name, which is mostly D, Bm and G. What makes it so difficult is that Edge is not your basic rhythm guitarist. he uses a lot of staccato and tends to play within the chords note for note string for string instead of playing the usual coffee house rhythm..not to mention the heavy delays. what you'll find with his use of delay is that he plays to the delay. he doesn't just use delay to color what he's already written sans effect.
you should learn, in first position, as many of the chords as you can - you're within striking distance of the most commonly used chords in U2 songs -- you need to add A, Am, Bm, D, Dm, F and you'll have much covered.
once you get those down on the first position you'll be able to get down further the neck and play with the voicings Edge uses. Good luck!!
or if just have tips.
You'll get the hang of it. 
