i bought a davis anemometer (forget the model, can look up if you are interested) for about $90 shipped. i then bought a digital bike speedometer for $10. the davis has an rj11 phone connector on it, so i got a phone wire coupler, a piece of 4 wire phone extension cord, and used this to splice onto the bike speedo. works really well, you just have to have a way to calibrate the bike speedo settings to match the anemometer.
i wanted a wireless setup, but just couldn't find something reasonably priced. you can use the same davis anemometer wirelessly, but you need a transmitter and receiver, which are about $200 each if i recall...so total price about $500.