I would like to know the same thing. Is there a way to receive a mail as soon as a pre-release of the Flash Player is released?
The last update to Flash Player 10.1 has caused some serious issues in our programs. A pre-release mailing list would really help us
There was a sign-up for notification for the Flash Player 10.1 beta for Android when it was announced. However I don't think that this was done for the desktop prerelease.
All I can say is watch the http://labs.adobe.com/ area for new developments.
Signing up for notification doesn't really help if Adobe never sends them. My whole company signed up to be notified, nobody ever received anything. You are better of watching the Labs (or grabbing an RSS feed from the Labs).
I go manually to http://www.adobe.com/software/flash/about/, or search in Google the terms flash about
On this page you will see the version you have and lasts versions of all the plugins on each platform.