Meeting people always seems to be a stimulus for jumping. To get a handle on this undesirable behaviour, establish in your mind what you want to see instead of jumping: sitting. In this exercise, you'll be rewarding your dog frequently so I recommend using your dog's dinner as a reward.
Establishing the alternate behaviour: reinforcing the sit
Practice the "sit" command repeatedly when walking your dog. Throughout the walk, call his name and ask him to "sit". Reward him for sitting every time with some of his dinner. Build some "stay" into the behaviour by using multiple rewards for every sit, don't forget to release with an "OK". If your dog gets really good at this, make it more challenging by trying to get him to sit while you are still moving.
Preparing for the greeting
Once you have mastered the "recall" and "sit" commands on your walks, you're ready to try the next step: meeting people.
As soon as you see someone walking down the street, call your dog and ask him to sit. Reward him. Say "OK", move a few steps, and ask him to sit again. Repeat this until you know your dog is starting to lose his brain because the person is getting closer. At that point, stand on the leash where it touches the ground, while still holding the handle. Reward him continuously as long as he remains seated. Stop rewarding him if he gets up. Don't worry, as long as you have your foot on the leash, he won't be able to jump or lunge.
Success comes with practice
Repeat this with everyone you encounter. Build value for the appropriate behaviour. Keep working on it. Your dog's jumping history and his general fondness for people will dictate how long it will take before he understands that he shouldn't jump on people. Regardless of how quickly he gets it, continue to reinforce his ability to sit when people approach. When you feel he understands to sit when approaching people start to increase difficulty by calling when the person is closer and closer.
If your dog is strong or a handful on leash, try having two leashes on your dog: one leash in your hand, the other leash under your foot. This gives you the ability to prevent the jumping while not letting go of the leash.
Let me know how you make out by commenting below!