Second Life 1.9.1 is now open on the Preview Grid!
The grid is open to adult residents born before March 27, 2006. You will find installers, release notes and known issues here:
http://secondlife.com/community/preview.php
Any bugs found should be reported with the in-client Report Bug tool. Be sure to include detailed description of the issue, including your system OS, a method to reproduce the problem, and any other relevant information.
Finally, see the 1.9.1 Preview forum for helpful hints, and to discuss new features in 1.9.1:
/290/1.html
Happy testing!