Earlier this month Adobe released a Flash Player 10 release candidate (10.0.0.569) for Linux. Over the previous betas, this release has improvement performance, fixes bugs, better V4L2 camera input, and fixes fullscreen video playback. It’s not likely that Flash Player 10 RC will make it into Ubuntu 8.10 because of the feature freeze.
If you want to try the new Flash Player, first remove any previous versions if you manually installed them. If you installed it from the repositories this is not necessary because the new package will replace the old one.