They are hoping to raise "close to $1 billion at a valuation of about $20 billion." [1]
And they still aren't turning a profit. (~15% loss Q1 2011 and ~54% loss in 2010) [2]
[1] http://online.wsj.com/article/SB1000142405270230374530457636... [2] http://www.sec.gov/Archives/edgar/data/1490281/0001047469110...