I've been playing in a flamenco band for a year. I have a jazz background, and I found the easier
palos (rumbas, tangos, sevillanas) not that hard to understand. However, I still had to learn all the signals that the musicians use to communicate among themselves since the form of a given song usually isn't fixed as it is in pop, rock, or jazz, but more or less improvised.
As for the harder palos that are based on a 12 beat compás, let's just say that I'm starting to get the feel for bulerías, but when the guys want to play a soleá, a siguiriya, an alegría or a fandango, I'm still getting my @$$ handed to me on a regular basis.
This book helped me quite a bit :
Amazon.com: Flamenco Bass Method (9788493445249): Mariano Martos: Books (Unfortunately it appears to be quite expensive in the US.)
Timo