| cool, i bike with my dog all the time, either on the leash or off. the way i got Chance to stay by me was first get the bicycle ready, lower the seat so you can put both feet flat on the ground to help you stay upright in case the dog pulls, which it probably will.
then put the dog on the leash and walk around with the dog heeling, changing direction abruptly and often, once you see the dog is really watching and paying attention to you, walk toward the bike and just ease onto it and coast real slow, pushing with one or both feet, hold the leash in one hand and the handle bars in the other. don't grab the handle bars with the hand that has the leash in it, if the dog yanks on the leash, it'll whip your front tire to the side and cause you to wreck.
pay attention to the dog at all times, if you see it start to deviate from the course you set, you will have enough time to react.
good luck, and probably should wear a helmet until you know how the dog will react out in public. | 
