The website is all contained on a Wiki so that anyone can contribute
How to edit
You can also click the edit button when viewing the website which is located on the bottom of each page.
Note that after you've changed the wiki it is immediately rendered on the http://cwiki.apache.org/ACTIVEMQ/ site so you can test it out; then up to an hour or two later it is updated on the Apache site.
How the site works
Other useful links are