The last really supported Flash for PPC was 10.1.102.64, but if it's for like Facebook or such, people have been fooling FB to think they have a leter version installed.
Texas Mac Man's Flash hack/post...
Flash player 11.1 hack on PowerPC - https://discussions.apple.com/message/16990862
Might be later ones around also... saw 11.3 I think.
(If you are running a PPC Mac with Flash Player 10.1.102.64 and are having problems with watching videos on FaceBook or other sites, contributor Texas Mac Man suggests the following solution which fools the site into thinking that you are running the latest version:)
Download this http://www.steelbin.com/FPforFBPPC.zip to your desktop, unzip it, and replace the current Flash Player plug-in which is in your main/Library/Internet Plug-Ins folder, (not the user Library). Save the old one just in case this one doesn't work.
You should also consider the Shockwave Player, which displays Web content that has been created by Adobe Director, much used for multimedia: For PPC Macs: http://get.adobe.com/shockwave/
See in each Browser which version of Flash it thinks it has...
Then Test Adobe Shockwave & Flash Players...
I am in the same boat. I cannot watch flash videos on the BBC website or on BBC iPlayer, although all other flash videos (YouTube for example) are fine.
For reasons that passeth all understanding, they work with the PPC version of Firefox, called TenFourFoxG5.app, once you have anabled plug-ins, as it does not natively support Flash.
You can download TenFourFoxG5 from here:
Now for the interesting bit: TenFourFox, like Firefox, does not support most plug-ins. Unless you are prone to headaches (in which case don't) you can read about that here:
But there is a workaround!
Open TenFourFox and type in the address bar: about:config (no spaces) and click return. This gives you a warning that it might harm the application. Ignore that and click on 'I'll be careful, I promise' and you get the config file that you can edit - with great care.
Look/search (scroll down) for: tenfourfox.plugins.enabled
Set it to true. (Double click it to toggle it)
Now close TenFourFox, open it again, and Flash will now work, as it now uses the plug-ins that Safari has stored.
I am using Flash 11.5.502.55 in TenFourFox and it works just fine.