About time indeed.
We've known about Plants Vs. Zombies 2 for quite some time, despite PopCap being tight-lipped on the details. Unfortunately it remains that way, but we did receive a somewhat humorous trailer announcing the sequel, which is officially called Plants Vs. Zombies 2: It's About Time. Release date: July 2013.
No announced platforms, but considering how well the original "got around," the odds of it appearing on iOS and Android are pretty, pretty, pretty, pretty good.