WordPress 3.0.5 has just been released.
It is a security release which is required if you have any untrusted user accounts.
It also contains other important security enhancements, so all users are encouraged to upgrade.
More information on the exact changes can be found here.
The release consists of 13 modified files, so it should be quite straightforward to update your WordPress website(s).
WordPress 3.1 RC 4 also released
WordPress 3.1 Release Candidate 4 is also now available. After nearly five months of 3.1 development and testing, it seems that the final version of WordPress 3.1 is just around the corner.