"Did you feel it?" – That is actually a link on this map, from the US Geological Survey, which charts the earthquakes around the world in the last 7 days.

You can report an earthquake if you felt it, through that "Did you feel it?" link, or zoom in from global to local on earthquakes around the world, to get details on the magnitude of the earthquake, its time, date and proximity to populated regions. There are also links to local earthquake measurement centers, or tsunami information for water-covered areas.

Another revolution in SMS text messaging – you can subscribe to a text service that will notify you of earthquakes and aftershocks in your defined area. The notifications are available within 5 minutes in the US, within 30 minutes outside the US.

Of course these notifications would be more helpful 5-30 minutes BEFORE the earthquake, but one assumes they are working on that.
http://earthquake.usgs.gov/eqcenter/recenteqsww/