I saw an ad for the last SG-1 episode last night, and they called it the "season ending," not "series ending," episode. So maybe there's hope?
Not from that. They divvy up their shows into late summer/fall seasons and then do a break and come back with a Winter/Spring season to finish out a full 22 episode season. This is the "season finale" for the late summer/fall portion of SG1 season 10. There are no plans for a season 11 at this time. SciFi has even stated that they will sue MGM if they try to shop the show to another network as SciFi says their contract forbids that. The rest of SG1 season 10 comes back after the first of the year.
This year they're adding a different set of shows with their own timetable and break, anchored by Galactica and others.