I think Flash Paint might be the best online art application I’ve found, at least for English Language Learners.
I have some other very good ones on my website under Student Paintings. However, what makes Flash Paint stand-out is that there is a place for the “painter” to write about their creation and you then can save the painting and the writing to the gallery. You’re given a url for both that can be posted on an online journal or blog.
The other web tools are great for drawing, but don’t have a place to write about it. This additional feature certainly enhances the language-development possibilities in using the site.