Mark,
Suggest you attend National Speakers Association events, especially their annual event. You will get to interact with some of the top speakers and learn quite a bit. Though restricted to professional memberships who get paid speaking engagements, others can also join.
I joined NSA in 1999 and since then been giving 40+ speeches annually. For a short period served the board of northern california chapter. Lot of credit goes to NSA and its members for my speaking success.
Glad to share more info if you need.
-Raj