This has quite a few interesting approaches for teaching writing and grammar for the Internet. Detailed research on how people read on the Internet. Lots of links...
This is a really cool site for collaborative writing and revision. This is like writeboards, but I think it's a little better.
This is a really cute, quick writing assignment. It would be a great way to talk about word choice (headlines), sentence structure, and how to write a journalistic intro. 9th grade?