Canonical has published the release schedule for Ubuntu 14.04
Alpha 1
December 19th
Alpha 2
January 23rd
Beta 1
February 27th
Final Beta
March 27th
Release Candidate
April 10th
Final Release
April 17th
Alpha 1
December 19th
Alpha 2
January 23rd
Beta 1
February 27th
Final Beta
March 27th
Release Candidate
April 10th
Final Release
April 17th