Google Docs

Google Docs spreadsheet with sharing options set so that anyone can edit.

A bug in updating means that after making changes it is usually wise to go to the Share button in the top right and click "Publish as a web page" and then press the "Republish now" button. Even if the the "automatically republish when changes are made" checkbox is checked it doesn't always seem to work.

Just add the publish code to your page using an iframe:

[[iframe http://spreadsheets.google.com/pub?key=0Akosof9g21FScHN4VW5fcndMNndwZHBqdmJpSEVnTkE&hl=en&output=html width="700px" height="400px" scrolling ="yes" frameborder="0"]]