I have to disagree with you, it's often not the skin colour but rather the passport you hold.  You'll find that if you come from a country where unemployement is low, the currency is strong and the standard of living is expensive, to move country you would demand more money. If you come from a country where unemployment is high, the currency is weak and living expenses are relatively lower, then you would probably accept a job that pays anything!

(Simple economics)

Unfortunately Western degrees are also more favourable to employers than many others.  

Take my example.  I am of oriental origin, but hold a British Passort and was educated in the UK.   My salary is on par or higher than many of my "white" counterparts (I'm not showing off, just making a point)!

So, although I'm sure it does happen, I find it difficult to stomach the idea that colour has very much to do with it, and believe that if it does occur, it is minority of cases and not the norm!