you've been assigned a Visa #

From http://uscis.gov/graphics/howdoi/immvisa.htm

If you want to become an immigrant, you must go through a three-step process. First, the USCIS must approve an immigrant petition for you, which is usually filed by an employer or a relative for you. Second, a visa number, through the State Department must be immediately available to you, even if you are already in the United States. If you receive an immigrant visa number, it means that an immigrant visa has been assigned to you. Third, if you are already in the United States, you may apply to adjust to permanent resident status after a visa number becomes available for you. (If you are outside the United States when an immigrant visa number becomes available for you, you must then go to your local U.S. consulate to complete your processing.)

這就是說485被接受後，你已獲得一個Immigrant Visa Number。

另外，請以美國務院Visa Bulletin消息為準。這則新聞也就不新了，請看

http://travel.state.gov/visa/frvi/bulletin/bulletin_2539.html