Pretend you are a poor Mexican (in Mexico) with no family in the US, and no specific offer of a job in the US. You want to immigrate so that you can look for a good job and live the American Dream (TM).
Let's also imagine for a minute that you have internet access (I know it's unrealistic, but it's the only way I might convince some of my readers to participate in this experiment).
Start at http://www.google.com/ and find the forms and procedures for you to become a US citizen.
This was as far as I got. Let me know if you have any more luck than I do.