At NAB 2012 in April, we announced an initial list of partners that licensed Smooth Streaming Client Porting Kit (link). Today, Roku announced that the support for Smooth Streaming is publicly available for Roku 2, Roku LT and Roku HD devices with version Roku software version 4.7. This update will be pushed to these devices in next 48 hours. You can get more details on their blog.
Congratulations to the team at Roku for this release. We are very excited to see the release.