37Signals just released a new product called Writeboard.
The idea behind the site is to easily and quickly share text between users as your developing copy for something. No account is needed to setup a Writeboard and they are password protected as well.
Once setup, you can even subscribe to the documents via an RSS feed to keep updated as changes occur. Looks like a really great tool for easy collaboration over the internet.
Be sure and check-out Writeboard to see how it may help you.