Looking through the oneworld website, it has links to the various airlines' status levels and associated benefits. On each of the pages it states that these benefits will be received when flying on any oneworld flight. (The actual wording varies, but that is certainly the implication.)

Of the Emerald levels it has the following to say about priority boarding:
BA Gold - Preferred boarding at your convenience, regardless of the class you are travelling in.
QF Platinum - Preferred boarding. You'll be invited to board at your convenience.
Aer Lingus Gold Circle Elite - Preferred Boarding: To facilitate a more relaxed boarding procedure, irrespective of your class of travel when travelling on a oneworld member airline flight, Elite members will be invited to board first or at your leisure.
Cathay Pacific The Marco Polo Club Diamond - Preferred boarding at your convenience, regardless of class of travel.
Finnair Plus Platinum - Preferred boarding at the member's convenience.
Iberia Plus Platinum - Preferred boarding at the member's convenience.
LanPass Comodoro - Preferred boarding: they can board the plane at their leisure, once the process has started either before or after Economy Class passengers.

But AA AAdvantage Executive Platinum lists nothing about boarding.

Is priority boarding a standard oneworld Emerald benefit or not?

If so (and it seems like the intention is that it is), does this mean we are entitled to join the First/Business queue when on a oneworld flight even if we are down the back? Or do we need to wait to be asked?

I don't want to miss out on a benefit if I am entitled to it, but I also don't want to be caught out trying to use a priority queue if I am not entitled to be there.

It's a standard benefit - no problem joining the F/J boarding line as an Emerald in Y. (The only caveat being if, for example, the Y cabin is not yet available for boarding due to, say, cleaning - I have seen this once...)

The EXP guide - linked from http://www.aa.com/content/AAdvantage...Platinum.jhtml talks about priority boarding. Is that what you were looking for?

but when you've got a late Final Boarding call in the QP or sim and are scoffing down the last drink, who cares!!!

christep, thanks for that - nice to have some confirmation.

ethan - you're right. I never noticed it there before - I thought the guide only talked about priority boarding on AA, but there in the oneworld section is the statement "preferred boarding and seating."

moa999 - yes I must admit that by the time I make it to the gate boarding is usually well under way and the wait isn't very long.

Wonder why the oneworld site neglects to list it in the AA Exec Plat section - oversight or incorrect information supplied I guess.

Normal boarding for AA EXP (Emerald) and PLT (Sapphire) flying AA is after F/J, but before Y. AA Gold (Ruby) boards with Y Group 1.