In Book IV of "The Wealth of Nations", where Smith discusses the systems of   
Political Economy, there's pretty extensive talk on colonial issues -   
especially chapter VII, entitled "Of Colonies". There Smith exposes the   
formation and peculiar characteristics of several colonial entreprises   
through history, and afterwards discusses the general structure and benefits   
of contemporary colonial arrangements. The general tone is against exclusive   
rights for the mother country, although Smith argues that, thus far, those   
arrangements had not yet been severely harmful for England.  
  
That should be a good starting point for your research.  
  
Carlos Eduardo Suprinyak