I was given a link by another educational professional to a very interesting page showcasing hundreds of useful tools for teachers – many of them completely free to use.
There are indeed MANY resources available for teachers online. Finding them is always the tricky part! However, Christopher Pappas has created a list of 321 tool/resource sites that teachers can use to accomplish just about anything for their classes and their teaching.
I have also added this link to the Tech Teachers Tools & Resources Links page.