Sony has officially discontinued the 20GB PS3's in North America heres the articles right here from the good ol [H]ard OCP.
http://www.hardocp.com/news.html?news=MjUxNjQsLCxobmV3cywsLDE=
http://www.hardocp.com/news.html?news=MjUxNjQsLCxobmV3cywsLDE=