So far PopCap has only released the long awaited sequel to their highly acclaimed game, Plants vs. Zombies in Australia and promised it to the rest of the world "later this summer." However, in a recent tweet dated July 31st, PopCap replied "Tell him to sleep in for at least the next week or so! :)" which could mean waiting for the second week of August. Since new iOS apps are usually released on a Thursday, you could expect to see Plants vs. Zombies 2 in your AppStore on August 15th!
Here is the original Tweet: