Hi samanthapost,
The obvious suggestion is to book everything asap, because Oktoberfest is extremely hard to organise something to the longer you wait. there are over 6 million people that visit within 2 weeks, so accomodation is at a premium there.
Here are some great tips / guide etc you may find useful:
Oktoberfest Survival guide:
http://www.oktoberfestpubcrawl.com/ (scroll right down, it's a PDF - their "history" bit is hilarious)
Oktoberfest A-z guide:
http://tntonline.co.uk/travel/destin...Festy-fun.aspx
The TNT site also has heaps of other great tips, and then there's the main Oktoberfest site at
www.oktoberfest.de (you can also get info on tent reservations there).
Have fun!