Adobe has announced Lightroom 2.3 Release Candidates are available for download.
Keep in mind this is a "Release Candidate", not an upgrade, and as such it will install separately from your current version of Lightroom.
When version 2.3 is released you will then need to uninstall the release candidate manually, as this housekeeping is not done automatically (though I think it should be).
If you have yet to make the Lightroom move and are wondering what all the broo ha ha is about, you can download a 30 day (fully functional) trial version here.
Keeping in the Release Candidate "theme" Adobe also announce the availability of Camera Raw 5.3 (RC).