Microsoft calls their Vista succeeding operating system Windows 7 internally.

Some details about Windows 7 have leaked from an internal sales presentation in Redmond.

The next Windows OS is expected to be released in 3 years (2010). There hav not been specific feature descriptions of Windows 7. Apparently the focus was on communicating that Windows 7 will have a more predictable release schedule than Vista, which is important for business customers. Lots of Vista users would rather see Microsoft focus on solving the current problems and not think about the next OS release. See this report about Vista from yesterday.
There is also still no word when Microsoft is actually releasing the Vista SP1.
More details on the Seattle PI.