How to profit from currencies?

[crazy canuck]

Suppose I can predict the direction of next weeks change of a currency with 65% accuracy. Also, assume the size of the movements I get right and worng is the same.

So what would be the best way to profit from this?

I believe if I buy an option, the time decay is too much. There don't seem to be any online brokerages either that deal with currency options.

Since the currencies barely move, holding the currency itslef instead of a derivative would be useless.

I guess that leaves futures. So is it then the only way to go? Does anybody know of a good online brokerage?

Any help is appreciated.