There's a nice description and a bit of background on the original painting from the State Russian Museum over on this blog.
And cartoonist and comics professor Lynda Barry has written an excellent essay on why copying artwork is such a good way of studying it. I agree, I don't feel I've really seen a piece properly until I've drawn it myself, learning all the different parts of it and wondering why the artist had a certain line ending in a certain place or admiring a positioning of colour to make something in the painting appear to leap forward. Read the whole essay on Lynda's blog.
