Mercury transit observed with TRACE
http://chippewa.nascom.nasa.gov/~dcm/transit/transit.html

Fred Espenak's wonderful transit site:
http://sunearth.gsfc.nasa.gov/eclipse/OH/transit99.html

Great info from the Association of Lunar and Planetary Observers (ALPO)
http://www.lpl.arizona.edu/~rhill/alpo/transitstuff/merc11_99.html

Another interesting transit site:
http://www.geocities.com/CapeCanaveral/7137/transit.htm

Royal Astronomical Society of New Zealand Transit site:
http://www.rasnz.org.nz/Transits.htm