Installing OpenIndiana or using it for a particular task, see Using OpenIndiana
Development, building the OS, packages, and upcoming releases, have a look at Developing OpenIndiana
2012-03-18 Change in weekly meetings
The weekly meetings moved from Tuesday 7pm UTC to Thursday 7pm UTC in #oi-meeting on irc.freenode.net.
2011-09-14 - OpenIndiana oi_151a released!