i tried playing with it an i saw no effect.
http://wiki.blender.org/index.php/Manual/Wave_Modifier
Needs verts, so if your just using a simple plane nothing will happen. Try testing with a default grid.
and then you do alt-A or change the frame number slowly and increase the frame number and you’ll see the wave move along the object
but it’s faster to see it if you animate it
Salutations