Google uses cool eLearning to introduce Wave
Got my wave invite this morning ( thx @jeffl8n ).
As soon a I logged in I checked out the first 'wave'.
Google embedded a youtube video of a guy explaining how to use wave.
It's nothing fancy (just 2 mins) but I think it is a good example of how eLearning doesn't have to by long and complex to make its point and keep users interested.
I made a screenr of it for you: