I highly recommend listening to this sermon especially for those who are interested in open air preaching and for those who preach and teach in general. I attended Dr. Montoya's seminar during the 2010 Shepherd's Conference. This message will help you to prepare to teach and preach, and reminds you of the principles in preaching and how to prepare prior to preaching. The link will lead you to the Shepherd's Conference page containing Dr. Montoya's message.
As A Dying Man to Dying Men, Alex Montoya (2010 Shepherd's Conference) (mp3 download)