Facebook has apparently already killed their experimental service named Find Friends Nearby.
Facebook Find Friends Nearby was not launched officially. It was leaked through some blogs online.
The feature was very powerful and allowed people in the same location find each other on Facebook to connect.
Looks like the publicity behind the app led to its sad demise. Facebook has not officially said anything about why the app is not online today. They might be working on fine-tuning it before an official launch at a later stage!