Notebooks based on the Geforce M and Quadro M family of mobile GPU's are capable of supporting two external monitors but it depends on the notebook design. Some newer notebooks are able to turn off their internal LCD and support two external monitors. Some notebooks support plugging three displays into their proprietary dock connector. Check directly with your notebook manufacturer for more details.
Notebook external dual monitor support
Updated 11/29/2012 02:06 PM
My notebook features one DVI and one VGA connector. How do I use two external monitors at the same time with my notebook?