I just saw this over on the Adobe Labs blog, Flash Player 9 Update Release Candidate for Mac Refresh Now Available.
If you are running a previous version of Flash Player on the Macintosh, I recommend downloading the latest version of Flash Player (9.0.98.0) from Adobe Labs. If you haven’t tried the latest beta of Flash Player on Windows, Macintosh, or Linux, head on over to Labs and take a look. The latest version of Flash Player, codenamed “Moviestar”, includes a lot of great things, including this snippet which I’ll copy-paste to save typing:
Support for H.264 video and HE-AAC audio codecs.
Multi-core support for vector rendering.
Full screen mode with hardware scaling.
Flash Player cache for common platform components, such as the Flex framework.
Support for Microsoft Active Accessibility (MSAA) in the Windows plug-in.
Adobe Labs – Flash Player 9 Update
You can also find more information on the latest Macintosh update over on Emmy Huang’s site, “Mac update for Moviestar on Adobe Labs to fix FileReference issue”.

what about the newer debug version?need it for Flex!
jerry,I’m not sure what version they are, but you could try downloading a nightly Flex 3 SDK build and see what version of Flash Player it ships with. The installers should be in the /runtimes/player/ folder.Peter
Also, for all you Apple users out there running (or considering upgrading to) OS X v10.5 (Leopard), I just noticed that http://www.adobe.com has a nice little 6 page PDF of frequently asked questions:
http://www.adobe.com/support/products/pdfs/leopardsupport.pdf
I also just noticed that Adobe has a nice technote on “Flash Player issues with Leopard (Mac OS X 10.5)”.