I'm spending more time on my hobbies of mobile photography and art, and MobileArt.how might be useful. It has tutorials for techniques and some of the popular mobile art apps in video and PDF formats, as well as a blog and forum for the community.
Free membership gets you into the forum and I think the first video of most of the tutorials series. For $50 per year you get access to all courses, full PDF lessons, and online support.
