Added a stub 'get involved' section on
http://www.mediawiki.org/wiki/Future#Core_projects and the other pages; there'll be more exciting stuff to see within a couple weeks as Trevor & Neil select testing tools & we all get started on prelim grammar descriptions.
We can pretty well expect to discard these initial grammar steps that we're doing as we get farther along, but we're going to need something to work with for now. :)
Collecting parser test cases & helping to document the existing parse tree formats in use by some other parser variants will be very useful while we're getting those together -- please feel free to add some notes to the AST & test case pages (linked to from the above) or post notes directly on wikitext-l.
-- brion