Regarding futures shops, there are prop firms and arcades. At a prop firm, you use the firm's capital and they take a cut of your profits. Training varies from firm to firm. Some firms also offer a draw or even salary for your first 6 mo. - 1 year. If you are not profitable by then, you'll be looking for a new job. Arcades are similar except effectively you trade your own money. You put up 5 or 10k, you trade out of their office and pay a desk fee. Payout is 100% and you won't get any draw or salary.

Anyone can join an arcade whereas prop firms are fairly selective. Geneva, Transact, Refco(actually not sure about this anymore since they went under), MacFutures all are well-known futures prop firms.