If you have been waiting for the first release candidate to try out WordPress 2.3, then that day has arrive. This morning on the development blog, they let everyone know that with less than a week to the final release, WordPress 2.3 RC1 has been put out into the world.
They also give a word of warning for anyone thinking of heading down the RC1 road:
Although we consider this release candidate to be stable, keep in mind that this is still pre-release software. You may find some lingering bugs. Please back up your database before upgrading. If you have problems with RC1, you will not be able to revert back to your previous release without a database backup.
Check out the full post on the WordPress Development blog.