I had something accepted by a publisher once (via a letter of intent to publish), but my package was a combo letter with a short comment about who referred me, the basis of my interest in the subject and some paragraphs about the proposed contents with a short outline, a copy of a draft for the introduction, a couple of the already worked out outlines for the chapters, then a few comments about the potential market for the book, some drawing samples, and a short personal resume. Alas, my resume (or bio) isn't included in my notebook on all this. I had varying resumes over the years and can only assume this was one that was not chatty, just listing various educational markers and some later projects/employment.
Depending on what the manuscript is about, I can see the bio being anything from similar to a Wikipedia entry paragraph(s) to regular resume form. On that, I'm sure there are some past a2k threads with good advice from people like Jespah.