Twitter lesson in person

I have a few startups and really need and want to get a handle on Twitter and how to use it and would prefer to have someone show me in person. I envisage it would be at the most an hour or 2. I live in London and I would like someone who is a Twitter maniac who uses it personally as well for others in a business sense. They should know how to use it for promotion and marketing etc as well as all the tips and tricks etc.

They should also be confident about teaching in a clear and understandable way.
Please indicate how much of a twitter maniac you are :) thanks.

(PS: The subcategories drop down isn't working on my computer)