Check here:
http://www.google.com/custom?domains=www.scsn.org&q=earthquake+swarm&sa=Search&sitesearch=www.scsn.org&client=pub-5676236325709660&forid=1&channel=7882517130&ie=UTF-8&oe=UTF-8&cof=GALT%3A%23008000%3BGL%3A1%3BDIV%3A%23FFFFFF%3BVLC%3A663399%3BAH%3Acenter%3BBGC%3AFFFFFF%3BLBGC%3A336699%3BALC%3A0000FF%3BLC%3A0000FF%3BT%3A000000%3BGFNT%3A0000FF%3BGIMP%3A0000FF%3BFORID%3A1%3B&hl=en
or
http://tinyurl.com/yo3aujEarthquake swarms are common, and the Southern California Seismic Networks keeps track of them, mostly in Baja California:
http://www.scsn.org/The long link above that I've tinyurled has links to every reference on SCSN to swarms, and you'll see that they have not led to major earthquakes. The article you link to as "precursor" was written in 2005. As you know from the lack of news, no one has predicted an earthquake from any evidence - swarms, cows, or aliens. :->