Helllllooooooooo
Help... I am a born US citizen with now dual nationality in colombia. I want to marry my girlfriend that I have been with for 2 years. We are both 25 with no kids, never been married. What are the steps I should take. I have already visited the INS website. But I want step by step.

You will first have to be married and then petition for her to come to the united states. My brother married my sister in law from portugal, and had to wait a few (don't remember it was 20 years ago) years for the paper work to go through. But your best bet is to speak to a lawyer. Do you live in the states? If you do, then that's another issue. Once an immigrant marries an american citizen, they can apply for a green card for the spouse. Again, there is a petition that you can file. You then wait for an interview where they will ask for proof of your marriage, pics, etc. they then will determine if it's a legitimate marriage and then will approve a conditional green card. Once two years have past after the conditional card is received, you then get a permanent one.

It is best to have an immigration lawyer for your wife, as the INS paperwork gets a bit redundant and confusing. I married a foreigner who worked in the US at the time we met. We married in the US, he was still here on his work visa, and then we went and had the interview to prove we were really married, not scamming. It took all of 15 minutes and now he is a conditional resident about to receive his permanent resident status.