http://press.web.cern.ch/press/PressReleases/Releases2008/ PR09.08E.html

Seems a faulty connection caused a helium leak in one of the sections of the collider, which may take up to two months to repair. CERN maintains that the collider is safe, and that this incident posed no threat to the public.

I'll keep you updated on how the repairs progress. Hopefully, we won't have to wait too long before they resume the startup procedures.

[Update September 25,'08]

According to the link provided by Mecha Destroyer JD, it looks like efforts are being delayed over the winter to save costs, pushing the completion of the repairs to early spring, 2009. According to the article, these sorts of troubles are to be expected, and we may see more to come before the LHC is fully operational.