Hello Todd,
Your questions are a good excuse to share all our info--I'm sure
you're not alone in your curiosity.
1. You can post to this Google Group via email (addressed to adwords-
a...@googlegroups.com) or via the web interface (http://
groups.google.com/group/adwords-api).
2. Pending API changes are posted in a number of places. This group
should always receive notification of downtime and new releases. Our
blog,
http://adwordsapi.blogspot.com/, is another place we post
similar information, and you'll also find longer how-to or best
practice articles there. There's also a very low volume Announcements
Google Group which you could subscribe to if you only want to receive
important announcements--it's at
http://groups.google.com/group/adwordsapi-announcements
3. Anyone can join this Google Group by visting
http://groups.google.com/group/adwords-api/subscribe
4. Google doesn't maintain such a list at this time. I've seen some
companies post in this group soliciting developers, which I don't have
any objection to as a matter of policy.
5. See the answer to 2. In general, if you're in this group and you
check the blog every so often (or subscribe to its RSS/Atom feed) you
should be covered.
6. For the time being, that's it. If we do adopt new ways of keeping
in touch with our developers, we'll be sure to announce them first via
all the old channels :-)
Cheers,
-Jeff Posnick, AdWords API Team