As Thundersnake says, many, many ways to watch youtube (and most other webvideo) without Flash, or even a browser. All of them beat flash on a ppc mac. Ok, one of them is flash. Here, lets list them, in order of bad-ass'dness:
4) Flashvideoreplacer (Firefox/TFF extension, copy the url, or download)
5) Downloadhelper (another extension, copy the url, or download the flv or mp4 file)
6) Viewtube (Greasemonkey script-replaces flash with quicktime. Works in webkit browsers as well with Greasekit)
8) Not a replacement but PPC Flash 10.1 can be replaced by a hacked version to look like 11.1 to sites that care...
9) HTML 5
10) TFF very own Quicktime Enabler
There are others. But these ten should give everyone a start point.
If you are using flash alone on a ppc mac in 2012 you owe it to yourself to investigate one of the above methods and then implement it...