Ah, here we go... as per:
http://www.debianadmin.com/ubuntu-70...ase-dates.html
Important Dates
December 2006
December 21st - Debian Import Freeze
February 2007
February 8th - Feature Freeze, Upstream Version Freeze
March 2007
March 8th – String Freeze
March 9th – Beta Freeze
March 22nd – Beta Release
April 2007
April 5th – Non-Language Pack Translation Deadline, Kernel Freeze
April 12th – Release Candidate(RC), Language Pack Translation Deadline
April 19th – Final Release