As an Euro (and someone with good inside knowledge in the football/soccer world) I find some posts here rather amusing.
No, these club academies don't expect the players to change their nationality as a return for educating them. Those European teams do it for profit and believe me they couldn't care less for the national teams. They bring them in because they hope to find a diamond in the rough.
Second the Dutch immigration law is now one of the more restricted in the world. Actually they lost one of the best African prospects (Salomon Kalou who now plays for the Ivory Coast) , despite pleas from legends like Johan Cruyff and team manager Marco van Basten to the (far right) immigration minister, because he was denied the Dutch Citizenship just before the 2006 WC (I think he failed the test).
As for the 20 Brazilians, the FIFA has actually taken some steps to clamp down on players claiming dual nationalities to qualify for national team selection.
To be eligible to play for another national team you must fulfill at least one of the following conditions:
a) the player was born on the territory of the relevant association;
b) his biological mother or biological father was born on the territory of the relevant association;
c) his grandmother or grandfather was born on the territory of the relevant association;
d) he has lived continuously for at least two years on the territory of the relevant association.
And on top of it, if you have dual citizenship you can only change your national association once and only if you are younger than 21 years of age.