Well aside from Mark Graham's hilarious "Zen Gosepl" ("Om, Om, sweet Om") there's Ferron's "The Return," although it may be slightly more Taoist than Buddhist:

Gonna lay my head on your blessed arms
Take my cue from the willow tree
For it don't break with just one storm
But bends witha will that keeps it free.

My song, "Prayer," which will be on my new CD, relates very much to impermanence and non-attachment:

May life abide and change from day to day
Where growth inside is a never ending way
And if I want this here and now to stay
May I find wisdom to move on and memory that remains

You'll have to wait a couple months for that one, though, or send me a pm.

Dan