Complete schematics as fritzing project. As some components are not part of fritzing application there are some notes. PIC16f628 was used. Crystal oscillator is 10 MHz one. Ceramic capacitors are 22pF. Link to schema: http://www.mediafire.com/download/wquqwb459oo6tn5/speedo.fzz

Magnet should be positioned somewhere at wheel, and REED somewhere on front forks. Distance between magnet and reed switch should be less then 10mm when magnet passing reed