After a very successful career, I recently sold my business to my partner. At the age of 59, I am raring to go and move on to other ventures. I would like to do consultant work for business' which are in need of executive level people without the cost. I am not sure where to start. Can you help me?

I don't think you necessarily need an agent to help you here. Your best 'agents' are your business contacts. Don't ask them for job leads. Take the best of them to lunch (one or two at a time) and explain that you're putting together a new business effort, designed to help smaller shops that can't afford senior level executives on a full time basis.
In others words, you're pitching the concept of a new business and asking for advice. If you handle this tactfully, you will turn up (1) others who may want to participate, (2) potential funding sources, and (3) potential clients.
The biggest mistake you could make, I think, is to act like you're looking for a job. The best thing you can do is to 'put the word out' that you're doing something new. Your business contacts know your success. If there's work out there, they will lead you to it, if you let them.