I had a duel problem with training my two guys on a leash
and I have to say that my watching Cesar Milan really did the trick
to get my two puppies walking on a leash very well
One of my guys was all over the place running every which way to check everything out
The OTHER wouldn't have any of it
He wouldn't budge
So I started with a follow training ... I took their favorite treat in my hand and told them to follow
This allowed them to focus
Then I did this with them on a leash and after a few sessions they got the message
The other thing is how you walk .... and this is where Cesar comes in
When you walk with a dog on a leash you are Leading them
there is no stopping for anything unless you want them to stop
Watch a few Dog Whisperer episodes ... he shows this technique a lot