When has it been released?

This product is not sold in stores. Rather it is sold by ordering directly through FFG (Print-on Demand Section), which assembles the orders and then prints them. It is available worldwide and from what i've read the international shipping costs are reasonable.

As far as I know translations are planned (for those of you who play translated versions).

E. g. in Germany you could get the PoD for MoM (original) in stores without problems. Not so with TMaO.

This ebay seller sells it worldwide for only 4.33 US$ shipping

http://www.ebay.de/itm/Lord-Of-The-Rings-LCG-The-Massing-At-Osgiliath-Expansion-GENCON-2011-Promo-Pack-/330629639071?pt=LH_DefaultDomain_0&hash=item4cfb0feb9f

My local gaming store got packs to sell in the store. I didn't realize that was going to happen.

The print on demand items are all supposed to be available to retailers:

http://www.fantasyflightgames.com/edge_npm_sec.asp?eidm=59&esem=1

Unless this is somehow an exception to their stated policy, it should be available to retailers, if they choose to stock it.