A lot of people seem to think monkeys are a flexibility issue, but I have trouble believing that. If you can squat down and touch your arms to the ground, in a -middle of monkey vault- position, then you have the flexibility to perform the monkey. If you can fit your legs between your arms, then you're good to go, its just a matter of committing, mentally. Andy's progressional tutorial will help you with that, but I don't think its flexibility. If you can squat down and touch your hands next to your feet, you can do a monkey.