Longitudinal and Transverse Wave Motion
http://www.gmi.edu/~drussell/Demos/waves/wavemotion.html
Earthquake Waves
http://www.geo.mtu.edu/UPSeis/waves.html
More about Seismic Waves
http://www.seismo.unr.edu/ftp/pub/louie/class/100/seismic-waves.html
Sound Waves
http://www.glenbrook.k12.il.us/gbssci/phys/mmedia/waves/edl.html
Making Your Own Sound Waves
http://www.physics.northwestern.edu/vpl/waves/sound1.html
Cool Picture!
http://antwrp.gsfc.nasa.gov/apod/ap010221.html