A PBW theorem for O_e(M_n), O_e(GL_n) and O_e(SL_n) over O(M_n), O(GL_n)   and O(SL_n)
  This paper has been withdrawn by the author. Its natural evolution is preprint math.QA/0610691, which is different enough to bear a different title (though they share about 2/3s of common content). 
Fabio Gavarini