Release of this alpha version of 64-bit Flash Player on Linux is the first step in delivering upon Adobe’s commitment to make Flash Player native 64-bit across platforms. We chose Linux as our initial platform in response to numerous requests in our public Flash Player bug and issue management system and the fact that Linux distributions do not ship with a 32-bit browser or a comprehensive 32-bit emulation layer by default. Until this prerelease, use of 32-bit Flash Player on Linux has required the use of a plugin wrapper, which prevents full compatibility with 64-bit browsers. With this prelease, Flash Player 10 is now a full native participant on 64-bit Linux distributions. We are committed to bringing native 64-bit Flash Player to Windows and Mac in future prereleases.
Adobe Labs - Downloads: Flash Player 10