I am coming to this rather late, I am sorry...but I am one to disagree with the "wait and see" theroy. (Although it is probably not an emergency and you don't have to get to a vet over the weekend...)
If he is still limping, I would say to go the the vet.
It is true that they most likely would just examine him and have you put him on rest...but (I say this a lot, so forgive me, but it is very important) DOGS DO NOT LIMP OR SHOW SIGNS OF PAIN/WEAKNESS UNLESS IT IS TREMENDOUSLY PAINFUL.
In the wild, signs of weakness can make a dog prey to other animals so they hide their pain and will not openly show discomfort. If they are showing signs of pain, you can bet it is extreme.
Therefore, I believe a vet is the best option. Then, if the vet give you the advice to wait and see, fine...he/she will be able to better judge what is happening as your dog gets progressively worse, if that should happen. But if you wait and take him in only when it is worse, the vet will start with the "wait and see" and not know that the limping has already progressed.
If it is due to a fall, your dog could have a cracked bone, or it could have hurt his joints, any number of things.
Personally, I probably pay my vet far too much money because I go in right away...but I have had my dogs go about their lives like nothing is wrong and days later have discovered something that must have been causing them great pain.
Whatever you decide to do is okay...I just felt that I should chime in and give you another point of view (the point of view from a panic-driven doodle mom...

)