Among those in the familiar format are the workshops and course material offered by Annenberg Media. They have more than 50 downloadable workshops in all major subject areas and grade levels. The materials are accompanied by video on demand to illustrate the ideas presented. This material is great for inservice and preservice workshops, and you have the option to purchase it if you prefer that to downloading.
For a different educational experience, I would strongly encourage you to subscribe to Edutopia's weekly e-newsletter. This newsletter is chock-full of examples of best teaching practices, innovations, technology in the classroom, and readers' recommendations. The Edutopia website has a section devoted to teacher development and many webcasts to instruct and inspire.
Another excellent source of training resources is Thinkfinity. Sponsored by Verizon and associated with ISTE, NEA and numerous content partners, their site provides webinars and professional development resources in partnership with each state to meet state standards. They also have an extensive catalog of online literacy courses for all grade levels.
For shear breadth and depth of resources, it's hard to find more learning materials than are available on MERLOT, Multimedia Educational Resource for Learning and Online Teaching. Their database of topics for professional development includes classroom management, educational foundations, technology & research, special education, and teaching methods, to name a few. Their materials are reviewed and rated by peers and users, and can be sorted in a number of different ways. Their peer-reviewed material is used by university faculty in many teaching courses. MERLOT's resources extend well beyond professional development to include material in all subjects for use in the classroom.
The Department of Education, Ed.gov, now also offers online courses. In Doing What Works, Ed.gov offers a database of the most effective teaching practices for preK-12. The database includes background materials, recommended practices, videos and tools. There is archived material in early chilhood education, English language learners, and encouraging girls in math and science. Although the subject offerings are limited, Ed.gov is working on more workshops, and you'll have the opportunity to participate in future online workshops.
Web 2.0 (the truly world-wide interactive web) is not just changing the way students learn, it's starting to impact professional development as well. TappedIn is a unique online meeting place where you can collaborate with other teachers, attend online course, mentor and find mentors. When you register you receive a monthly listing of topics, dates and times. Take a look at the TappedIn Calendar to see the types of courses and discussions offered.
More than one teacher has asked me about using Second Life virtual worlds in the classroom. I really know next to nothing about it yet, but I have found a few sites teachers can visit to get the scoop. One is Literacy to Learn (L2L), hosted by USDLC and sponsored by the Dept. of Education. They have archives of past sessions, with additional sessions planned for this fall.
Another virtual worlds forum is RezEd, with group discussions and podcasts on a broad range of topics. They've just completed a Global Kids Second Life curriculum, where students from around the world can address global issues while applying and learning skills from multiple disciplines.
A more complete listing of professional development resources can be found in the LearningReviews.com Professional Development websites section. You might also find my website listings for Project-Based Learning and Collaboration & Networking helpful.