From Dark Horizons.com
This past season "Galactica" ran the first half of a season from August-November, and then the second half from January-March - a formula that's worked for the Sci-Fi Channel's "Stargate" shows for nearly ten years.

Next year however whilst both "Stargate" series will still follow the old mold, "Galactica" has been pushed back to a fall season premiere. The 20-episode third season of Battlestar Galactica will now begin in October 2006 - thus likely indicating the series will run its course with little to no interruption instead of enduring a two-month mid-season hiatus.

The network did not give a reason for the later premiere date. The show's ratings have dropped significantly this season, along with the rest of the network's Friday night line-up which could've pre-empted the move.
Best show on TV and its ratings have dropped =(