Physics Classroom
The Physics Classroom: Newton's First Law of Motion
A clear explanation of Newton's First Law of Motion, the law of inertia, with diagrams and real-world examples. Useful for both students and teachers. Written by a high school physics teacher.
Science and Mathematics Initiative for Learning Enhancement (SMILE)
Smile: Newton's Laws of Motion
Lesson plan from the Illinois Institute of Technology that incorporates many demonstrations like pulling a tablecloth from under a place setting, or launching a rocket to show Newton's laws.
NASA
Nasa: Beginner's Guide to Aerodynamics
This site from NASA discusses application of Newton's first law of motion to airplane motion. Includes a graphic and an accompanying explanation.