WordPress has released updates to both it’s 2.0 and 2.2 branches. These are regular bugfix/security updates and do not (so they claim) affect any plugin or theme functionality–so they should be an easy upgrade by simply overwriting your files with the new ones. As with any security upgrade releases, it’s really a good idea to upgrade as soon as you can. You can download the updates from the main WordPress.org website.
Home » Software Updates » WordPress 2.2.2 and 2.0.11 released