The USGS still offers the best worldwide earthquake resource, and there are a few widgets out there using its feeds. My favourite is the Yahoo Widgets Earthquake (above) which gives you a little world map displaying earthquakes as they happen.
The USGS also has a range of RSS, Twitter and other data feeds, including a Google Earth KML overlay.
A novel experiment called USGS TED (Twitter Earthquake Detector) analyses Twitter for references to quakes and plots them using the Twitter geolocation information.
It's fascinating science, but as the unfortunate citizens of Haiti know only too well, earthquakes destroy lives and even countries. If you want to find out how you can help, there's a widget the top of this blog, or alternatively you can go to the donation page at the UK Disasters Emergency Committee (DEC) site.
[Update 23/1: removed Red Cross Haiti widget as it wasn't working]