IEEE Xtreme Link: www.ieee.org/xtreme
I myself did not participate in the IEEE Xtreme 6.0 competition held last month (Oct-2012) but I did manage to get my hands on the material provided to the participants, including the FAQ Page, the Sample Question and the actual-competition-Questions.
All are provided in a not-so-neat-PDF
P.S.: here is the questions PDF from IEEE Xtreme 5.0