Toastmasters International holds a lot of resources that can be useful for Public Relations.
If you would like to contribute/share materials on this subject please send them for publication to firstname.lastname@example.org
If you are looking for sponsoring for your club, area, division or district conference you will want to know the Toastmasters Policy for Fundraising: Protocol 8.2: Fundraising
If instead it is your club that is sponsoring some kind of event remember that each club is an autonomous entity and the members can decide what to sponsor, but make clear that it is the club which is sponsoring. In the case of a request for sponsoring from Toastmasters the following policy applies: Policy 5.0: Corporate and Community Activities