Gunnar Langemark has pointed out a new company that provides a hosted Drupal service: Bryght From the site:
Bryght is our Drupal hosted service that enables anyone from individuals to businesses and organizations to easily build and maintain a dynamic website with an online community.
I’ve used Drupal for a couple small project groups. It is a great collaborative tool if you can keep everything html based (document management tends to be a bit weak). This service should make it feasible for a much wider array of people to easily take advantage of Drupal.