The Flash Player team posted a release candidate version of Flash Player 10 to the labs.adobe.com site, http://labs.adobe.com/technologies/flashplayer10/. which includes some new features and bug fixes.
So download the latest version from http://labs.adobe.com/downloads/flashplayer10.html, check out the beta release notes, and don’t forget to uninstall any versions of the Flash Player before updating your installation.
Plus. after installing the latest version of Flash Player 10: Astro, why not check out the Flex Gumbo beta! There are a few examples of downloading and installing the Gumbo beta SDK over at blog.flexexamples.com.