UPDATE: Please test personas-1.6.2rc2.xpi, not rc1, thanks!
A Release Candidate of the Personas Plus add-on for Firefox 4 is available on the FTP servers. The RC works both with the current nightly builds and Firefox 4 beta releases.
The more testers the better, so we could really use your help. You can download the add-on here: https://ftp.mozilla.org/pub/mozilla.org/labs/personas/ — you want to get personas-1.6.2rc2.xpi.
If you find any issues, please post a comment here or in the bug. Thanks!