i had the same problem. what has worked for me with my almost 8 mo. old Boxer is when company comes over put him in a sit/stay before he can have any attention. at first i had to use a short leash because he wouldn't stay for very long before getting back up(he was too excited). but after he realized he wouldn't get any attetion until he was being good and not jumping he hasn't jumped on anyone else.
another thing to try is have treats by the door when guest come in to get a treat and make him sit then give the treat to him and pet him as long as he isn't jumping.
no matter what you try to stop this behavior be patient and persistant