This is a link to the Scholastic pages on Thanksgiving. It's an extensive section of their website, there's a lot of information.
http://www.scholastic.com/scholastic_thanksgiving/
We especially would like to point out the interview with Fast Turtle a member of the Wampanoag Nation on the Scholastic website. In this interview Fast Turtle plays the role of a Wampanoag in 1621. The interview gives us a window into what it might have been like during the time of the first Thanksgiving from an indigenous perspective. Here's the link to Fast Turtle's interview:
Plimoth Plantation Website is full of information. Here's the link for the Plimoth Plantation home page: http://www.plimoth.org/
Of special interest is their award winning on-line activity for kids where they take on the role of "history detectives" to investigate what really happened at the famous 1621 celebration we call Thanksgiving.
Here's the link for the kids Thanksgiving on-line activity "You are the Historian" - http://www.plimoth.org/learn/MRL/interact/thanksgiving-interactive-you-are-historian