Amazon has been providing quite a bit of information recently — yesterday with the “Trilogy info”, and today with the Viz Big info! We now have releases dates going into early/mid next year, so here is a quick breakdown for you (including ones that are already out, since it gets a little confusing):

Dragon Ball:

• Viz Big Volume 1 (tankōbon 1-3)
  03 June 2008
• Viz Big Volume 2 (tankōbon 4-6)
  16 September 2008
• Viz Big Volume 3 (tankōbon 7-9)
  16 December 2008
• Viz Big Volume 4 (tankōbon 10-12)
  17 March 2009

Dragon Ball Z:

• Viz Big Volume 1 (tankōbon 17-19)
  03 June 2008
• Viz Big Volume 2 (tankōbon 20-22)
  19 August 2008
• Viz Big Volume 3 (tankōbon 23-25)
  18 November 2008
• Viz Big Volume 4 (tankōbon 26-28)
  17 February 2009
• Viz Big Volume 5 (tankōbon 29-31)
  19 May 2009

Remember, this does not even include all that “Collector’s Edition” stuffage that starts coming out in October of this year, which appears to be single volumes as opposed to the omnibus-style “three-in-one” packaging…