As a friend wrote to me, "This morning at 4:45 am [California time] the Sun crossed the equator signaling the first moments of the Spring, and the start of the Persian New Year :-) The site http://www.timeanddate.com/news/holidays/vernal-equinox-2008.html has a good explanation of what constitutes March Equinox."
Foreign ministers of Persian speaking countries celebrated Nowruz in Afghanistan.
Patricia Khashayar has written a pretty good report on Nowruz for Press TV. Press TV also carries a report on an underwater Haft Seen in the Persian Gulf.