'Stargate Atlantis' canceled, kind ofSource: TV Squad
Well, this is just all kinds of disappointing, and a little surprising. Season five of Stargate Atlantis will be the end of its run on Sci Fi. That's a surprising bit of news considering that ratings are actually up for season five, compared to season four.
Stargate: Atlantis Renewed for Season FiveSource: SCI FI Wire
SCI FI Channel has renewed its hit original series Stargate Atlantis for a 20-episode fifth season. Produced and distributed by MGM Television, Stargate Atlantis is set to resume production in early 2008. Its fourth season is currently airing Fridays at 10 p.m. ET/PT.

Zap2it.com posted a story reporting that Paul McGillion will return to Stargate Atlantis in the upcoming fourth season in a two-episode arc, along with Torri Higginson, though not necessarily in the same episodes.
Firefly's Jewel Staite Joins 'Stargate Atlantis'Source: SCI FI Wire
Producers of SCI FI Channel's original series Stargate Atlantis told SCI FI Wire that the upcoming fourth season will add former Firefly cast member Jewel Staite to the cast as a new doctor.
Stargate SG-1 cancelled, Atlantis renewedSource: gateworld.net
Sci-fi continues to befuddle science fiction fans. Instead of the cancelling the show at many natural cancellation points they renew - now that there is a story in place to carry the show couple more seasons - they cancel.