Hmmm, documenting a lineage to George Jacobs Sr (ca. 1617-1692) is a process, which I am sure you know. Here is a link which provides a nice overview of him. www.findagrave.com/.../fg.cgi?page=gr&GRid=8639
More can be found in the Salem Witch Trial Archives at the Univ. of Virginia (online).
Sidney Perley's History of Salem, Mass. Vol III, has quite a bit about George and his family.
How far along are you in your research?