Zynga's hugely subscribed massively multiplayer online game, Farmville, is coming to iPhone.

A new client is coming to the App Store sometime in summer, in order to help grow the user base beyond its current 70 million strong players.

"Farm any time anywhere" is the slogan, as quoted by Mark Pincus, CEO of Zynga, who has also revealed that all Facebook friends can be accessed in the iPhone version, and use all of the same social functions.

With such a massive game, it certainly seems a good fit for the App Store, with the only question being why has it taken this long...