In light of yet another possible tsunammi after an early morning Indonesian earthquake today, I would suggest subscribing to the UNESCO IOC service which disseminates the tsunami advisories issued by the Pacific Tsunami Warning Center, West Coast /Alaska Tsunami Warning Center, and the Japan Meteorological Agency (Indian Ocean only). Simply enter your email address and click the submit button to subscribe. You will then receive advisory messages.
Note: this is not an operational service and these messages should not be considered as official warning messages. Official warning messages are assured of delivery only to the Tsunami Warning Focal Points and other national authorities.
Go here to subscribe; http://ioc3.unesco.org/itic/contents.php?id=142