Dan Harrington has a good HeadsUp section in his Vol. 2 tournament play book for NLHE. You should check it out.
That's a good book, and the HU section did help my Heads Up play.
Icecold24k, be forewarned that there's no magic to playing heads up. Often the blinds are so high that you're forced to make some big moves.
If I recall, he goes through the classes of hands and goes through some of the odds. Basically, you're both going to have non-optimal hands most of the time.
Harrington goes through an entire session with Phil Ivy vs someone else, showing their hole cards and explaining their motivations.
More than anything I think that part just gave me confidence in my heads up play. IE, there's no magic bullet to it. You just do what you can with what you have. That confidence allowed me to concentrate more on my opponent than on my own cards and all the other stuff that I can't control, which improved my game.
So yes, I recommend Harrington on Hold'em Volume II, but I think you should read Volume I first, and when you do get to the HU section don't be disappointed if it's not as detailed/complex as the other sections of the book.