Exact release dates have not yet been announced. Normally Online TurboTax begins the first week of December. This has been the case for several years, and there's no reason at this point to suspect that it will be any different for this year than previous years.
Desktop software (CD/download) usually begins shipping to Advantage members (annual subscription) after mid-November, and available to the general public in late November/early December. TurboTax also starts accepting pre-orders for the desktop software a few weeks prior to release.