See http://support.microsoft.com/default.aspx?scid=kb;EN-US;q313807 for details.
See also http://www.microsoft.com/downloads/release.asp?ReleaseID=34507 for the direct download (although there is a download link in the KB, too). -Scott List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm
