How long does it take to migrate my kids if I have a green card?

Depends on what country of birth their case would be charged to. I recommend you file an I-130 to establish a place in line for your son and perhaps qualify him for the child Status Protection Act and that you file for U.S. citizenship on the soonest date that you are eligible. His case would currently fall in the FB-2a category which is backlogged to April 1, 2007, longer for persons born in Mexico or China. Once he turns 21 he automatically is moved to the FB-2b category. Once you become a citizen his case will be upgraded to immediate relative if he is under 21 (or eligible under CSPA); it would convert to FB-1 if unmarried son of USC and over 21 or FB-3 if married son of USC over 21. Each month the State Department puts out a chart (called the Visa Bulletin) of the dates they are working on for each category based on the date of filing the I-130. I would suggest scheduling an appointment for a consultation. We do charge for consultations but whatever fee is paid for the consult would then be a credit toward the fees for your case if you retain us for further immigration work on your behalf.