I have never used screen cast before and to be honest, it was not looking very promising due to some technical problems with Java. It took me weeks and multiple occasions of forcing a computer shut down before I could record anything, but now that I have used it I see that it is incredibly easy! I know of some teachers who have used screen casting to record lessons for a long distance student, and I can see how it would help. However, for language arts and social studies, I am not sure how I would be able to use it in the classroom other than to show directions for different programs I use in projects. (See my screen cast)
Screen casting could help with teaching how to cite resources, especially when looking for information on websites. As this is a topic that needs to be reinforced all year, I could see myself posting screen casts of citation techniques and tips throughout the year, especially in conjunction with projects and research. This would also be useful for the students to use when writing a "how to" paper. They could use the screen cast to help them write or double check their work, making sure they covered all the steps clearly for others to repeat the process and be successful. I think I am starting to see screen casting in a whole new light.