I ran across a website for artists that is rather comprehensive, called Empty Easel. This website has only been up for two years and as far as I'm concerned, they get a whole bunch of thumbs up. They have something for everyone in every medium you can think of. I found them while doing a quest for tutorials on stretching canvas.
There are quite a few tutorials, you can submit articles, submit your art, learn how to sell your art on line, a business advice section, research, featured artists by medium, an electronic newsletter to subscribe to, and on and on. I hope you check it out and go back often as it is NOT a static site at all! The two geniuses behind all of this have also sell a website service called foliotwist. If you re looking for a way to get your own website up and sell your work on line, and want full control over managing your site (and you really should), this is a great way to go. I've looked at what they have to offer and one of the features that really has me sold (other than having full control over the site with the ability to send out an electronic newsletter to your clients) is that there is no limit to how many images you can have on the site. The list of bells and whistles goes on and on-I am truly impressed. Especially with the flat monthly rate which is affordable. I won't tell you what that rate is; you'll have to click on the link and find out for yourself!
Even if you don't utilize their web services (which is foliotwist), the Empty Easel site is chock full of information and many great resources. I would encourage each and everyone of you to take advantage of what is there and perhaps to submit your art or an article to them. Who knows what will happen?
I should also mention that Daniel Smith has a great section of on line instruction and video demonstrations. Do you have other on line teaching resources and sites that you would like to write about and share?