Pretty excited to finally see a released, just found this, so i haven't tried it yet, but here is a link.
http://www.haiku-os.org/news/2009-09-13_haiku_project_announces_availability_haiku_r1alpha_1
http://www.haiku-os.org/news/2009-09-13_haiku_project_announces_availability_haiku_r1alpha_1