For Free Take, For Buy Waste Time...

My Dad used this phrase from time to time in our family hardware store in a variety of contexts...But it comes back to me in the same way. Like now.
Just thinking of some of the fabulous free online resources/web apps that can be turned to our benefit in the classrooms. Besides the more common Flickr, wikis, and podcasts, I'm curious to know what other free resources/tools that teachers are using these days.
It seems very good business sense to put these new tools in the hands of students and teachers-for the benefit to the kids-and on a less altruistic note, for the customers they'll soon be.