I really enjoy visiting youtube for educational purposes. The videos are usually so short which helps with keeping students engaged. Since attending the in-service with Alan November, I especially love to visit KhanAcademy and wolframalpha.
When reading about fair use and copyright, educators can pretty much use whatever as long as the entire work is not copied or the entire collection not scanned. It all brings back memories from high school and making sure not to plagiarize will writing papers.
I love the idea of using Picasa. The real life images are great for quick sets and also for visual support my ESL learners.
On to tool 4 and 5.