The updates to OPF and OPS (two parts of the three that make up the EPUB standard) for 2.0.1 were published by the IDPF on 25 May 2010 at
http://www.idpf.org/specs.htm:
*
http://www.idpf.org/doc_library/epub....0.1_draft.htm
*
http://www.idpf.org/doc_library/epub....0.1_draft.htm
I the final versions will be published after all of the formal review hurdles have been completed, but my understanding is that there haven't been any substantive changes suggested, so they should be about the same.