How can I make whole wheat bread and biscuits with out the bitter taste?
Part of the problem is that whole wheat flour goes rancid pretty quickly after it's milled (I believe it's from the natural oils in the germ). The usual advice is that whole wheat flour has a shelf life of six months or so, much less than white flour. If you're using old flour, try getting fresher stuff.

If you're willing to go through extra effort, consider milling your own whole wheat flour; after reading this article: http://www.realbakingwithrose.com/2006/11/rose_levy_beranbaums_100_whole.html I got a grain mill attachment for my KitchenAid mixer and started milling flour, and I've become a total convert. Fresh-milled whole wheat flour has an incredible taste. My standard loaf these days is 50% whole wheat and 50% bread flour, and it tastes great. It has a nice nutty flavor without the tree bark or cardboard you'd normally associate with bread with so much virtue in it. I've done 100% whole wheat loaves before, and while they're very good, they're just not my thing.

If you want to get even further into it, Peter Reinhart has a book on whole-wheat bread making, which has special starter techniques to get the best flavor possible. I realize your question is about biscuits and not necessarily bread, and his book doesn't have anything to say about biscuits or quick breads.