thanks to meb for turning me on to the power-assist newsgroup at Yahoo
groups. this is the place for the latest info on power-assisted bikes.
there is a spinoff group called e-motor-assist at Yahoo that is also
interesting. most of us pedal along at least part of the time but add
electric motors to our existing bikes or buy/build custom ebikes.

you can buy a kit that will give your existing bike electric motor
capability without interfering with your ability to pedal along without
the battery. for under $400 you can convert your bike to electric with
a top speed without pedaling of 20-30 MPH for 7-15 miles on a charge.

-bob