At the LISA conference last week Apple's Director of Engineering of Unix Technologies Jordan Hubbard showed a slide that stated a release time frame for the next major OS X release of Q1 2009.
Apple previewed OS X 10.6 aka Snow Leopard at the WWDC08. Back then Apple stated the release date to be in one year. Since the WWDC 08 took place in June that would have meant Q2 of 2009.
Now hopes of an earlier release of Snow Leopard will grow amongst the Apple community.
Apple could even launch Snow Leopard at the MacWorld 2009 in January.
More details on MacRumors.

Rather than focusing primarily on new features, Snow Leopard will enhance the performance of OS X, and improve quality.
Snow Leopard is optimized for multi-core processors, taps into the computing power of graphic processing units (GPUs), enables larger amounts of RAM and features a new media platform with QuickTime X.