This is a) beautiful and, b) an extremely rare original piece of art created as a cover concept painting for LucasArts' Monkey Island 2: LeChuck's Revenge. This concept was one of three and was not chosen for the final painting. The painting is 7" X 10" was done in gouache (an opaque watercolor) on heavy illustration board and has been covered with acetate since it was created in 1991. This painting was included as a full page reproduction in the Rogue Leaders book and, as we all know, original artwork from LucasArts rarely, if ever, becomes available for sale. This one has been painted -and is being sold by- Steve Purcell himself.
Have a look at Steve's site (announcing the auction) here and go bid on this amazing piece of Monkey Island 2 art over at eBay. US buyers only, I'm afraid.