This is all supply and demand. That's why Bush, an ardent Capitalist, wants to give amnesty. There is a demand for cheap, reliable labor in America. Mexican immigrants provide that in a more dependible and uniform manner than America's lower classes. Hence, to fulfill the supply, they hop the border. Around where I live I see Mexicans everywhere, doing construction, picking crops, etc. The native Americans simply did not fulfill the demand for labor, so Mexicans came.
Zephyr