I hope you are aware of latest WordPress 3.0 released to the public recently and WordPress 3.0 is the 13th major release of WordPress which involved 218 contributors.
Great Features and Enhancements of WordPress 3.0
1) Around 1217 bug had been identified and fixed.
2) Bulk updates enable you to upgrade 15 plugins at once with a click.
3) Merging of MU and WordPress which create the new multi-site functionality from the same installation.
4) New default WordPress theme called Twenty Ten is included in this release.
How To Upgrade WordPress 3.0
You can either upgrade within your WordPress dashboard or download WordPress 3.0 Installer(2.2MB) from WordPress.org. Please refer to How To Upgrade WordPress post to learn the easy way to upgrade WordPress.
To find out more great features or enhancements of WordPress 3.0, please watch the below WordPress 3.0 video tour to see the real WordPress 3.0 “Thelonious”