If everything goes well, Debian 6 should be released in the first week of Feb, 2011.
Neil McGovern posts on the Debian mailing list, "...we now have a target date of the weekend of 5th and 6th February for the release. We have checked with core teams, and this seems to be acceptable for everyone."
We can be confident about the release on the scheduled date as the second release candidate of the installer for Debian Squeeze is available and is being tested for remaining bugs.
However, the scheduled release might get affected owing to unforeseen factors such as a server crash, a critical bug or any other technical challenge.
Debian has 3 versions, stable, testing and experimental. The stable version has been updated to 5.0.8 today. Debian is considered to be one of the most stable distros. Many popular distros including Ubuntu and Mint are based on Debian.
If you are a Debian user, participate in the testing and help the team find and fix bugs.