The official Stargate SG1 & Stargate Atlantis is a go for 2009. The convention dates begin on Thursday the 2nd April 2009 and end of Sunday the 5th April 2009, and will be held in Vancouver.
So far there are only 3 of the shows leading roles appearing at the conventions, these include:
Joe Flanigan
Amanda Tapping
Connor Trinneer
Further details will be released closer to the time.