Yes. There will be multiplayer. Lots and lots of it.
The most basic multiplayer support is for those that only have one iPhone or iPod with them: Passing the device.
The second kind of multiplayer is local networked play: You and your friends can connect to each other using WiFi or Bluetooth (Don’t worry, you don’t have to setup up anything - it just works.) and play against each other using multiple iPhones or iPods.
Last, but certainly not least, there is Internet play. You can invite friends to play via the Internet, or join a quick game against random strangers on our servers.