Matz announced a release of the snapshot of Ruby-1.9.0-1 at the ruby-dev mailing list yesterday.

• http://www.ruby-lang.org/ja/news/2008/03/01/ruby-1-9-0-1-snapshot-released/ (Japanese)

%%1.9.x%% 1.9.0-x versions are for development and
so this release is not stable.
It has fixed some bugs and not fixed others.

At any rate, files are here:

• ftp://ftp.ruby-lang.org/pub/ruby/1.9/

Original Source

• Ruby 1.9.0-1 snapshot released

Updates

• 6 March, 2008. Corrected the mistaken version number 1.9.x mentioned above to 1.9.0-x. Thanks Ryan!
• 24 March, 2008. Added the original source which hughperson told me at reddit.com. Thanks!