There's a new project on Wikipedia that aims to cover the varying laws regarding electric bicycles.
http://en.wikipedia.org/wiki/Electric_bicycle_lawsEmerging Laws Specific to Electric Bicycles
Motorized bicycles have been around for many years and are considereded mopeds in most jurisdictions - particularly if they are powered by a gasoline motor. The past few years have however seen an emergence of electric bicycles as a viable alternative to gas-powered motorized bicycles...