Hhhmmm... What about us antipodeans?
I'd be tempted to run this for my local game shop.
So is this restricted to the US and if the Uk is included any idea where?
Does this need to be requested by a game store willing to run it and can anyone explain how they dealt with this previously in the earlier seasons or series?
I'm not 100% sure about Australia, but I think this is available in most territories where WotC operates.
It's distributed via the same organised play network that Magic: The Gathering uses, now folded into an organisation called the Wizards Play Network. General information is here:
http://www.wizards.com/wpn
If the programme is available (and it is available in the UK - I organise it in Sheffield) it must be run at a game store. This is one of the major ways Wizards is trying to encourage game stores to host D&D games, and people to play at stores. The organiser - who needn't be a store employee and needn't end up GMing if they can find people who will - needs to register as a WPN organiser, which can be done from the WPN website. Once the WPN have verified that the venue details entered when registering are a retail store, the organiser should be able to create an event in the WPN online system, and then Wizards will send the kits out to the registered stores. There's a particular window during which this event creation has to take place, though I don't think sanctioning for the third season of Encounters is open yet, so new people have time to get it sorted.
Far more advice can be found on the WotC forums and groups, particularly
the WPN forum,
the D&D group and
the RPGA forum. Feel free to PM me for more info.
Players looking for places which are hosting Encounters can use the
Wizards Event Locator to see if their local store is running the current Encounters events (they're set in Dark Sun).
Hope that helps! (Oh, and I just had a look and there are some Australian stores running Encounters, so it is available). The main limiting factor is that it is only available to retail stores; WotC has other organised play programmes - particularly Living Forgotten Realms - for people who aren't lucky enough to be near an FLGS.