The Battlestar Galactica reboot, which starred Edward James Olmos, Mary McDonnell, and Jamie Bamber aired from October 18, 2004, to March 20, 2009, and ran for 4 seasons. The original series, which aired from July 7, 1978 to April 29, 1979 and starred Lorne Greene, Richard Hatch, and Dirk Benedict, only lasted a single season.
There was also another short lived series that was a spinoff from the reboot titled Caprica. This series starred Eric Stoltz, Esai Morales, and Alessandra Torresani, and lasted only a single season airing from January 2010 to November 2010.
Hopes for another televised spinoff, titled Battlestar Galactica: Blood & Chrome appear to be dashed after a trailer leaked to YouTube was removed and officially labelled as unsanctioned.
All is not lost, however, Syfy President of Original Content Mark Stern is quoted as saying that there will be a new series, it just won't be televised as a first run, it will be a web based digital series.