Sitecore published a document that describes how to implement ASP.NET Membership Providers. I have updated my post that provides links to the best Sitecore documentation.
John West Blogs about Sitecore
http://byfiles.storage.live.com/y1pAeuioQgoQrEslsG44piKREOnUmDDq6cyVWLM45XGJml_f4hJoWktuYf5Z5ahYmwi