Google Docs

Google Docs
http://docs.google.com or http://www.google.com/intl/en/options/

According to Google "Create and share your projects online and access them from anywhere"

Google Docs can be used as a repository for your documents, large files, presentations, and graphics that you need to make available to a group of individuals.

You can determine who can access them or make them available to the public at large. Google Docs allows you to involve multiple individuals in the editing, composition, or reading of documents.

Great for groups that need to work on a document and have access at various times. This keeps one document that is common to all - do away with versions and trying to figure out who has which version.

Many Word type features are available such as comment, spell checker, strikeout, and bookmark. It also reads PDF, Word, RTF, and HTML versions of documents.

It's easy to use, it's available on any computer connected to the internet, and it's free.