What questions can I expect in a supervisor or team leader interview? Please help?

I suspect you might get a few of the following:

Why do you think you would be effective in a supervisor or team leader role?

How can/will you motivate your team?

What makes a good/effective team?

What areas of your performance might you need to improve to become a better team leader?

Are you comfortable taking disciplinary action against a team member?

Chirs's responses are good. You might also get a lot of open ended questions like;

Give me an example of something you have done ( in or out of work) to indicate you have leadership capabilities;

How would you handle a situation like.... ( employee late or your manager is pushing you to get something done and you know your team wont be happy ...how will you achieve the goals;

They may also raise the fact that you will now be leading or supervising people who were your peers and they will be testing you. How will you prepare to tackle this supervising people who were your "friends"

good luck