Start by checking out your local chapter of the National Speakers Association? Our Illinois Chapter is very friendly, encouraging and resourceful.
This group will have lots of connections you're looking for. If I were you, I'd find a virtual assistant for speakers and let them manage all the details - there are many. For example, it's important to have your own contract and your own marketing materials. I go so far as to build in a marketing/PR campaign to promote the audience members as well as the organization.
To connect with other speakers, you might also ask your questions on www.speakernetnews. com, www.speakersite. com [a new social network for professional speakers] or LinkedIn - in a group like "Speakers and Panelists" or "Public Speaking Network."
And, feel free to browse Wired PR Works' speaker marketing/PR category.
Are you a speaker? What resources do you recommend?