The challenge is only for topcoder members that attended the Forcelandia conference. The goal of this challenge is to build the coolest app using the Untappd API. We have contacted the guys at Untappd and have expediated the process of provisioning API access.
Once you've logged into Untappd, you can register your new app here. Make sure you use the keyword that was supplied at the conference in the last text box.
If you are having problems getting your API access approved please post it to the message boards.