Sculpting in concrete?

[NedsTJ]

Does anyone know any good books or websites they can recomend for scupting in concrete? Disney creates a lot of neat rock features from what I think is just sculpted concrete over wireform. I want to create a few features like this myself for my garden railroad this summer. Looking for tips, tricks, helpful advice sort of stuff for beginners.
Thanks!
For Example: post 20606, last photo:
http://www.disboards.com/showthread.php?t=836587&page=1374