The release schedule for the upcoming Ubuntu 12.04 LTS operating system has been published on the Ubuntu wiki. The distribution will be released at the end of April 2012.
Note:-codename for Ubuntu 12.04 LTS has not been chosen yet
Ubuntu 12.04 LTS Release Schedule
1St December 2011 - Alpha1
2nd February 2012 - Alpha2
1St March 2012 - Beta1
22nd March 2012 - Beta2
19th April 2012 - Release Candidate
Note:-codename for Ubuntu 12.04 LTS has not been chosen yet
Ubuntu 12.04 LTS Release Schedule
1St December 2011 - Alpha1
2nd February 2012 - Alpha2
1St March 2012 - Beta1
22nd March 2012 - Beta2
19th April 2012 - Release Candidate