We're getting hundreds of reports of failures with Second Life, starting about 9:15AM SLT (US Pacific). Problems reported include all transactions, inventory, map problems, profiles, balances, teleportation, sim border crossings, IMs and ... well, pretty much every service. Users are reporting that logins are not only failing, but crashing the viewer.
This includes the Second Life website, which is non-responsive, though the Linden blog is live (it is not hosted with the rest of Linden Lab's equipment).
Update: After about 1 hour and ten minutes, the problem has been resolved. No information appears to be forthcoming on the cause or the cure. Thus we do not know if we can expect this to happen again today.