CLDR Development Site
Some of the key pages for developers are:
CLDR: Big Red Switch (checklist for release)
The subpages listed give more information on internal CLDR development. See also: Sitemap.
Note: when editing Sites pages it is often useful to clean up HTML in material pasted in from other sources, such as Word or Google Docs. Some useful regexes for that:
Also see the Google Docs to Markdown extension, by edbacher