Pinballvideos.com is the best for searching.
Searching by pin on Youtube also works: it will pull up the PAPA tutorials, TNT tutorials, Buffalo Pinball tutorials, etc.
It will not capture the videos that are archived on Twitch.
Pintips.net is a good resource for a few quick hints.
Tiltforums.com is great discussion board resource for all the newer pins, including nuances when code gets revved.