Like bsimon said, their 8 page pdf is still legal but it's so old that it's like trying to run Dark Eldar in 40k. Just too many weird rules.
There is an unofficial Chaos Dwarf Armybook that's on the GT circuit right now. I'm trying to convince warhammerworld to let me take it to Sooie.
If you're interested in starting an army, load up on Skull Pass. It's perfect w/ all the goblins and dwarves. Just a little conversion work and you're rolling.
I'm actually eyeing a Chaos Dwarf army based on Mantic Games' Dwarf range, but it's all in pre-order status.