Originally Posted by Giles
...If I understand OW correctly it is a way to accumulate miles on an OW member carrier when flying a different OW member carrier? And that once those miles have been posted to that particular carrier they cant be transferred to other member carriers?or can they?...
That is correct. However, you should be aware of the gimme and the gotcha.
The gimme is that you can use AA miles for QF awards and vice versa, as well as use either kind for awards on other OW partners - or on long flights that involve multiple OW partners. Specifics are in the "Using Miles," "Awards" or some such section of each partner's Web site. Check the site of the airline(s) whose miles you would use.
The gotcha is that some airlines only award fractional credit for miles flown with partners in discount economy class. Again, specifics are on each airline's site. In your case, a cheap Qantas ticket would earn only a fraction of the AA miles that an equally cheap AA ticket on the same airplane (they codeshare many US-Oz flights) would earn.
Another gotcha that many people unfortunately only learn about after the fact is that BA trans-Atlantic flights to/from the US don't earn AA miles. That could affect you if you get seriously bitten by the mileage bug and decide to go to Australia the long way round! (It can be cheaper that way, too - but you may have to check that routing in two parts because some sites won't think of it themselves.)