We've taught all our freshman and juniors, and some of our seniors.
Some of them use it more than others, but my coworker and I think iGoogle is one of the most useful tools out there so we're sharing with as many kids as we can.
I don't have much specifically for teaching students, but I did professional development sessions on all of the above...
I didn't have real lesson plans, but I did create notes of what I wanted to cover and in what order. The notes probably make more sense to me than anyone else, but hopefully they help a bit.
They can be found here: iGoogle homepages Calendar, Docs and Reader