Lots of apps in the iTunes App store for your iPhone when hitting up the Wiesn this year:

Official Oktoberfest app.

Oktoberfest App 2012

Oktoberfest Guide

What tents are open, what rides are closed due to a long wait. Get up to date info and check your alcohol level in your blood. And if you can still walk, learn to ask to sit in that empty seat in Bavarian. Nice.