Ubuntu 12.04 LTS Precise Pangolin free download iso
Ubuntu 12.04 with code name Precise Pangolin is set to release final version in April 26th, 2012 as stated by Mark Shuttleworth. Though Alpha 1 released already. If you want to try this Alpha 1 version go through below links to download full iso cd of Ubuntu 12.04.
Click the below link.
PC (Intel x86) desktop CD
64-bit PC (AMD64) desktop CD
64-bit Mac (AMD64) desktop CD
Mac (PowerPC) and IBM-PPC (POWER5) desktop CD