So I just found out the release dates for Mass Effect over at Playerone.be. Here's google's attempt at a translation:
"Microsoft has just announced the date of precise exit of its play Mass Effect on Xbox 360. New the RPG of the Bioware studios will unload finally next on June 5 to the United States and the 22 of the same month in Europe, thus confirming the last rumours in date. The American giant will propose two versions, including one collector with a metal case, a DVD making of and a artbook for 5 euros additional. A guide will be also marketed in the United States (traditional and Limited Edition) by the Prima company, but the exit in Europe remains dubious at the present time. Let us recall that Mass Effect will propose to leave to discovered many planets in an evolutionary scenario. Indeed, just like in KOTOR, or Jade Worsens, your actions will affect the destiny of all the forms of life in the galaxy."