Go to your local bike shop and ask them. At my shop we sell CatEye Cycling computers. Cateye is for the most part the most widely known cycling computer. Other manufacturers include Shimano, Campagnolo, and Planet Bike to name a few. Computers usually have anywhere from 5-8 functions and can tell you not only your speed but, time, total distance, average speed, your cadence (rpm of your legs) top speed and more. Some computers are wireless, while others can be coupled to your shifting system (depending if the shifting system is compatable) and can tell you all sorts of other information about your cycling. Campagnolo manufactures a self learning computer. Computers can range from $15.99 for the basic to over $300.00 for the Campagnolo self learning cycling computer. (please not, these prices are "ballpark" and will vary at different bike shops) Either way your local cycling store should be able to help you choose the computer that is correct for you, both in cycling needs and budgetary constraints. If not, go to my shop and e-mail us! see the link in the source section below.