Mora knives are good for general use. Good quality, not expensive, not too heavy. After looking at one, I plan on picking one up as my camp knife.
I don't really whittle per se, but for a while I was a wood carver by trade. I was trained by my cousin in northwest coast native art, and our preferred tools are crooked knives and adzes. We made our own out of circular saw blades, but I've bought them pre-made from a place called Kestrel before. A quick web search shows me that www.caribooblades.com
sells knives that are closer to the style I'm used to. Click on their "hookknives" link and they'll show you the way we hold 'em: blade down. They offer excellent control, and are easy to use for carving spoons & things on the trail.
I don't have any books to recommend; I'm afraid all my knowledge was either gained from my teacher or experience. I wouldn't have a clue how to whittle using a straight knife, but I'm sure there are good books out there somewhere.