Well, as I'm holding a copy I assume it's already out.
AS to what's in it it has a new Ranger and Paladin core classes. It has a few prestige classes (all divine oriented) as well as a bunch of spells , some feats, some domains, etc.
Actually it's only one domain but yes Book of Hallowed Might by Malhavoc Press IS available both in print and PDF. (I don't believe there's any difference between the two) It's really a wonderful suppliment if your a divine spellcaster of any stripe (though mostly it's best for clerics and paladins with a few druids spells mixed in.) Overall it's got some great ideas on how to use a varient alignment, varient paladins, and even determing costs for casting certain clerical spells. Plus Hallowed Mage kicks MUCH butt if you want to be a wizard/cleric in any campaign. (My opinion of course.)
Are you thinking of the BOOK OF EXALTED DEEDS, the sequel to the BOOK OF VILE DARKNESS? Wizards is putting that one, by James Wyatt and about using good in a mature campaign, out in the fall -- October, I believe...