If you're interested in finding good quality copyright free or creative commons licensed online material for creating your own mashups then this website is a great resource.

The 2011 competition is now closed but the winners are listed and show what great work can be done.

The site also has a great guide for educators looking to create their own projects. Downloaded the guide now:

• Free to mix: An educator’s guide to reusing digital content (PDF / 1.6MB)
• Free to mix: An educator’s guide to reusing digital content (DOC / 1.6MB)

The guide gives you information, activities and ideas to confidently create a remix from material you know you have the rights to reuse. It shows students why copyright and licensing exist, how they work, and how they can apply licences to their own work through simple information, suggestions for activities, and links to more resources. By using it, you and your students will be able to participate in the global remix community while demonstrating creativity and integrity.