I had a pair of speakers from a bike shop years ago that clipped on the handlebars and held a walkman or whaever. I haven't seen them in years, I got mine around 1990. That sure made it great for riding to the beach
http://www.bicyclestereo.com/accessories.html
http://www.bicyclestereo.com/system.html
Found that in 30 seconds after posting. Search is our friend