Defination : Tsunami
Tsunami are a Japanese term which has been used to describe a large seismically generated ocean wave, produced by a submarine earthquake, landslide, or volcanic eruption.
The pronunciation for tsunami is "soo- nah- mee", and comes from Japanese : tsu (port) + nami(wave).
Incorrectly referred to as tidal waves, Tsunamis have no connection with tides.
Here's the USGS info for the Dec 26 '04 Preliminary Earthquake Report. Other links on the disaster: WorldChanging; and Wikipedia has great and uptodate coverage.
For news and information about resources, aid, donations and volunteer work, the best source is The South-East Asia Earthquake and Tsunami weblog and impromptu short-notice clearinghouse.
Did the earth move for you?
Richard Gross, a geophysicist with NASA's Jet Propulsion Laboratory in California, theorized that a shift of mass toward the Earth's center during the quake on Sunday caused the planet to spin 3 microseconds, or 3 millionths of a second, faster and to tilt about an inch on its axis.