Many times I allow the children to use the Internet to research and find their own images to add to their projects. However, I am very weary of Google and Bing, simply for the fact that they are not filtered and nearly anything can come up by simply searching for french fries for example. I love Google for myself, and I use it often, but it makes me uncomfortable to let the children use it on their own. Therefore, I searched for some kid friendly search engines and came across searchenginewatch.com whichs lists quite a few good ones! Here's some to name a few...if you know of more, please add to my list!
Ask Jeeves for Kids
Looksmart's Kid Directory