When is cataclysm coming in stores

Q u o t e:
"Soon".

Lawyered ;-)
http://www.wowwiki.com/Soon

On a more serious note; we haven't yet provided a release date for Cataclysm, although we have said that we would like to get it released this year if possible.

Don't worry though, an announcement will be made once a release date has been set :-)