YouTube
Linden Lab has an official Second Life YouTube channel at youtube.com/secondlife. It includes educational and entertaining videos such as feature tours of Viewer 2 and various video tutorials. Content continues to expand as the channel grows, as it's relatively new.
Torley Linden, master video tutorial maker, explains further:
How do I subscribe?
On youtube.com/secondlife , scroll down and look at the left-hand side for the yellow Subscribe button.
How's this different from secondlife.com/video ?
secondlife/video is a shortlink to the video tutorials.
Going forward, the YouTube channel and secondlife.com/video will have the same video tutorial content (which is fed from VodPod), but the latter is specifically designed and integrated with secondlife.com (alas, that also means right now you need to be logged into the website). It may be easier to find things using the tags on secondlife.com/video
I was expecting to find a tutorial when I used youtube.com/secondlife but it didn't show up!
First, this channel only has the new-ish tutorials starting with Viewer 2. Old ones are still shown on secondlife.com/video .
All new videos state what Viewer version they were filmed in near the beginning. This makes it easier to discern if something may be out-of-date.
I have a video tutorial request!
The best topics for video tutorials tend to be (1) stuff that's hard to explain in words but easy to understand by showing and (2) broadly useful for many Residents — this includes obscure features many people can benefit from... if only they knew.
Torley welcomes video tutorial suggestions! Contact him directly.