When VLC was last updated for PowerPC it was possible to play Youtube links copied into it - alas that ability has long since expired but you can bring it back with a few updated components.
This only applies to the last PPC iteration of VLC, version 2.0.10 and also requires the ever wonderful PPCMC (for latest security certificates and curl.)
The following code copied into Terminal will do the following:
Make a directory in VLC preferences for the latest security certificates
Delete the old Youtube lua script from VLC
Create a symlink in VLC preferences of the security certificates in PPCMC (this will update when PPCMC is updated)
Finally, using curl, copy the latest Youtube lua script into VLC
From the download here extract the compact Youtube browser, Choob and the VLC scripts, VLSEE and VLLISTEN into Applications and create shortcuts in the dock (right hand side for VLSEE/VLLISTEN as they are scripts.) Open VLC and in Preferences - /Input/Codecs change the Preferred video resolution to Standard and close.
Opening Choob, browse to your chosen video, right click to copy the link then click the VLSEE dock shortcut - VLC will open and quickly stream the video - quit VLC when finished.If you want to stream audio only then do the same but with VLLISTEN.