There is a good book called the Power of Now by Eckhart Tolle. It is VERY esoteric and kinda "new-agey" but his philosophy is very eastern in the fact that he stresses not dwelling on the past OR the future as they are both constructs in our own mind, and as such, are NOT real.
Another one is the Little Book of Letting Go. That one is a bit more palatable and a much easier read. It's mainly about how to train yourself to let things go, to not dwell on them and let them control your life. I would actually suggest this one first.
And, of course, DB/DR also talk a lot about how to take your mind off things by detaching and GAL.
