If you have not visited iTunes U, I highly recommend checking it out. You will find a wealth of videos, lectures, and podcasts from several major universities. You will need to download iTunes before you are able to access iTunes U resources
Applications for Science Teachers: Teachers can use the resources at iTunes U for their own professional development, such as brushing up on science content. There are also many video and audio clips that would be appropriate for sharing with students. These resources can also be accessed/downloaded on iPods and iPhones.
Yale just recently added content to iTunes U- so this could be your opportunity to get the Ivy League education you always wanted- for free!