Sorry, this is a bit late, but wanted to share.

Did you find what you were looking for?
Yes and no. I was looking for videos to address how humans can affect the lives of animals… for 8 year olds. I found a variety of videos and interactive stuff that might work for my unit. They do exist!

How did you know if you could use it or not?
I went to a known source that would have a plethora of materials for educators (teachers domain). They have a similar system to CC which distinguishes the rights of the material on their site. I always looked at the “terms of use” for details.

If the CC license was obvious, that was, of course, very easy (Gooru shows this when you hover on the icon).

Share what worked (new search tips!) and what didn’t for you.
I relied on some known entities to find what I wanted (teachers domain, paid databases), but explored some new areas like Gooru and OERCommons. I love both of those, but they required a little more involvement to find what I wanted. OERcommons almost has too many options, and it will either take time to figure it out, or you must take the time to examine each of the resources in detail (since the result page doesn’t show you much detail of each item). Gooru looks very cool, and organizes the information by type, which is very helpful, but it does not allow you (that I can tell yet) to filter by age level appropriateness. This is a big challenge.

Another useful tool (I did not use this time) is to used advanced search in Google to filter by a particular CC license. Might be useful for others.

For images, I discovered a few great ones from reading different blogs referred to here in this course. One I love is Flickrstorm and Flickrcc. Then again, the more I look, the more I find stuff that is so useful (and I get lost in exploring!). However, one I have found in the past and LOVE is Pixabay with mostly CC0 images.

I stumbled upon several great collections of sites on copyright friendly resources. I know there are more, but here is just a start. I think I was led onto this path from a comment in one of the P2PU “Teach Someone Something with Open Content” units.
http://copyrightfriendly.wikispaces.com/
http://www.only2clicks.com/pages/joycevalenza/343504
http://milicopyrightwiki.pbworks.com/w/page/20921908/Links