YouTube Live Streaming is now available for channels with 100 subscribers.
by Bern Rexer
Previously your channel required 1000 subscribers for live streaming. This news heard from VidCon opens up live streaming considerably for anyone with a YouTube channel.
It was also announced in the YouTube Creators Blog http://youtubecreator.blogspot.com/2013/08/investing-in-you-more-tools-to-build.html and confirmed on the YouTube Live Operations product forums:
YouTube Live Access Expanded
If you have more than 100 subscribers then check your account features and select Enable for Live events.