cold front
warm front
occluded front
stationary front
weather fronts
fronts
fronts and air masses
These links provide information on air masses and how the interaction between different air masses form different types of fronts.
http://www.bbc.co.uk/dna/h2g2/alabaster/A34944582
http://www.auburnschools.org/drake/aklecompte/Storms%20Review.htm
http://www.wunderground.com/blog/LRandyB/archive.html?year=2008&month=05
http://www.auburnschools.org/drake/aklecompte/Storms%20Review.htm
http://www.rossway.net/occludedfrnt.htm (image from http://www.physicalgeography.net/)
http://www.nvwx.com/nwssymbols.php
http://ccrc.unh.edu/~stm/AS/Weather_Toolbox/NE_Weather_Primer.html
http://www.muhs.acsu.k12.vt.us/academics/NHurlburt/Weather%20Fronts%20notes.htm