Iterations
Sputnik aims for time-based release management. Kind of like Ubuntu does it. That is, the goal is to make a release roughly every six months or so, regardless of the features. The development is organized into cycles or "iterations". Here are some of the recent ones:
Fenchurch is the latest iteration, aiming for a release in February or early March of 2009.
Earth was the iteration from Feb to Aug. 2008.
What Can I Do?
If you want to help, please ask on the Mailing List.