NASA has some incredible resources for educators. Here's another one.
The famous Jet Propulsion Laboratory has a great education site that has a lot of great resources. There are resources for students and educators on topics such as Discovery Guides about the planets and NASA Missions, classroom activities, videos, multimedia resources, and much more. There are after-school activities, teacher professional development, and in-depth projects to use.
JPL also has internships for students, which are a great opportunity for students to get some great learning and experience.
The site is easy to navigate and the resources are excellent. They can be used in any classroom.