First of all, Stargate SG-1 is being renewed by the SciFi channel for another season. Apparently its renewal for season 7 was in doubt until quite recently.

Also, in a surprising development Michael Shanks is returning as Daniel Jackson. Of course in season 5 Daniel Jackson supposedly died. So did somehow survive in captivity? Did he get underground and avoid the nuclear blast? Or will a supernatural element come into the equation to bring him back? Jackson already showed up in a supernatural form in the episode where Colonel Jack O'Neill was being held captive by the Goa'uld. I hope the way Jackson returns is not too cheesy.

Richard Dean Anderson and Amanda Tapping have already signed on the dotted line to return as well. Even thought Dr. Jackson is returning the Jonas Quinn character played by Corin Nemec is expected to return as well. Ditto for Teal'c as played by Christopher Judge. Richard Dean Anderson is still going to be the star but he's not going to show up in as many scenes.

I don't know what the creative disagreements were that led Michael Shanks to leave SG-1. But I hope the writers inject some elementes of the original movie Dr. Jackson into the returned Michael Shanks Dr. Jackson. The original Dr. Jackson from the movie version was a more mischievous and curious academic whose curiosity and willingness to interact with and get to know an alien culture were crucial elements of how the movie plot developed. The TV show Dr. Jackson was a less interesting figure and what he thought and did were less crucial to the plots of most episodes. Samantha Carter's hard science knowledge played a role in how episodes developed far more than Jackson's soft science and history knowledge did.

You can read the SciFi.com announcement and a couple of posts from gateworld.net here and here.

Update: There is also a Slashdot thread running on this topic here.