Already out in a few european countries. For the UK itll be released either this friday the 26th of June or the following week on the 31st. The games obviously gonna be brilliant, realism, vehicles and just like in the previous games great teamwork.
Heres their site with some screens to drool over.
http://www.arma2.com/
EDIT: Ekhem the game has been in shops since the 19th of June....