Looks like some artists at Marvel are going to have to start working for a living again.http://www.comicbookresources.com/columns/index.cgi?column=13
It is the first article on the page. Essentially, Marvel is emphasizing that they expect all artwork submitted to them to be original. Reference material is okay, but no more tracing.
I for one am happy about this, but I've actually seen some people upset because they rather have photo-realism than original content.