I would start by bringing the lead around the pole or other object (don't wrap it), and stand there holding it. When the horse stands still, give lots of praise. When he moves, take him by the halter (under were the lead clips) or by the start of the lead and give the 'whoa' or 'easy' command. It is crucial to be patient and calm, don't start with tying until the horse is comfortable with the idea of being tied.
Being tied goes against all of a horses instincts so you just gotta be patient and work at it. x)
A reward system could also be useful. Some grass, or chunks of a favorite treat given when positive behavior is achieved can help a horse gain confidence and trust in the trainer. A tasty treat encourages relaxation and more positive behavior.
I myself don't give treats EVERY time something I want occurs, a good scratch or a rub on the head also conveys the 'good job!' message. I do not give ANY treats if pushy or nippy behavior begins. I demand respect and a calm attitude if any treats are to be given.
I have been using a reward and punishment system with my three year old with awesome results. He is not nippy or pushy, but instead is much calmer and quieter around people, and is easier to handle in general.
Wait! I'll fix it....