visual studio 2008

Enable parallel compilation in one project (there are many restrictions though):

http://msdn.microsoft.com/en-us/library/bb385193.aspx

3rd party alternative

http://www.todobits.es/mpcl.html?gclid=CMvLxJGFzKECFRAbewodXkMkfA

How to use #import directive (which cause conflict with /MP option)

http://msdn.microsoft.com/en-us/library/8etzzkb6.aspx