WordPress 2.6 contains a number of new features that make WordPress a more powerful CMS: you can now track changes to every post and page and easily post from wherever you are on the web, plus there are dozens of incremental improvements to the features introduced in version 2.5.
There are several new features in WordPress 2.6. The WordPress team have also created a video that demonstrates the new features bundled with WordPress 2.6.
Happy upgrading and gud lak!
[WordPress 2.6 – WordPress Blog]