The newest version of WordPress has been released (2.2) and can be downloaded from the WordPress.org website (you can use the link off our left bar over there if you’d like).
As with any major number release I suggest NOT running right out and upgrading your site immediately. If possible try to upgrade a local or non-live version of your site first. Major number releases tend to change certain behaviors of WordPress which can cause older plugins or themes to break. Based on my testing my plugins will work fine, but even so I will be doing the same technique as they suggest:
1) backup your site files and database.
2) de-activate all plugins.
3) replace the regular files with the new files
4) go to www.yoururl/wp-admin/upgrade.php and run the database update function
5) log in and reactivate all of your plugins
6) test EVERYTHING!