* FlashToHTML5 (3.2) – Free – PowerPC Friendly 10.5 Leopard. It is a Safari extension that replaces the standard YouTube Flash Player with an HTML5 player. Download Here.
* Youtube5 – PowerPC Friendly – Free – Leopard 10.5 – It removes the need to use flash on YouTube by converting all videos to their HTML5 video tag equivalents. It also has the added benefits of decreased CPU usage compared to flash, and the removal of in-video ads. Download Here
The TenFourFox QuickTime Enabler allows you to play selected HTML5 video and audio files and YouTube videos in QuickTime, outside of the browser. You can even play H.264 content with the QTE. This gives you a safer alternative to Flash for many videos.
If you got a little bit excited by this, you can download the 2.12 Beta 2 as they encourage testers and will be more than happy for you to discuss and report problems you may encounter, as they work to improve their product.