The Song of Wandering Aengus by William Butler Yeats and nearly 2,000 other poems from all corners of the poetic universe can be found at Abraham Thomas' and Martin DeMello's Wondering Minstrels site. http://www.cs.rice.edu/~ssiyer/minstrels/index.html should get you there. If this link fails simply google 'Wondering Minstrels'.
It's a great deep blue peaceful place, almost like the bottom of the sea, to go to read, to study, to explore, to leave comments on and so on. For simplicity, ease of use, lack of clutter, and amazing content it's got to be one of the best poetry sites on the internet. P-i-R says "Check it out!"