Venture capital investors in Facebook include Accel Partners, Andreessen Horowitz, Elevation Partners, Founders Fund, Greylock Partners, Kleiner Perkins Caufield & Byers, Meritech Capital Partners, Millennium Technology Value Partners and Technology Crossover Ventures.
Here's a link to the Bloomberg story: http://www.bloomberg.com/news/2012-03-02/facebook-adds-deutsche-citi-credit-suisse-on-ipo.html