search for free online courses. One resource that I neglected to mention and subsequently had many people on Google+ remind me of is Coursera. Earlier this spring Coursera announced a new category of courses, Teacher Professional Development. Currently, thirty courses are scheduled in the new Teacher PD category. The next course begins in July.
Applications for Education
Coursera's new teacher PD courses include topics like First Year Teaching, Virtual Instruction, Assessment, and Developing Relationships. You will also find courses that are content specific. For example, there are courses on Genetics and Society, Introductory Physics, and Art.