The trick is really to moisturize your hands (and everything else) right out of the shower in the morning (or whenever you shower) and right after washing your hands. The trick is to lock the moisture in, not try to get it in there later. My girlfriend will be proud that I know this...
Gloves help a lot too. "Mechanix" or similar type gloves keep you from taking a lot of little nicks and cuts that contribute to cracking and hand pain. The only time I'm not wearing them is when I'm using tape or working with particularly tiny parts.
I have been known to wear vasoline filled gloves at night to help this problem. I look like Mickey Mouse, but it works. Besides, the lights are out anyway.
I haven't found a good lotion to make it thru our Maine winters - but I do use super glue to seal over the cracks that are deep and painful - works great, no pain, and washes out with Lava, usually at the end of the first or second day....