For Permanent Worker Visa, you can have a company sponsor you. How long does the sponsorship have to be?

If you wish to change jobs some time in the future, is there a set time you have to work for a certain company before you can change? Do you have to fill out a new form for this or can you just change?For Permanent Worker Visa, you can have a company sponsor you. How long does the sponsorship have to be?
you can change job at any time after you get your green card. you don't have to fill out any form or inform USCIS about job changing after you receive your green card.



under I-485 Portability (AC21), you can also change job while your employment based green card petition is pending in USCIS. the new job must be the same as, or similar to, the job described in your labor certification and your petition. you will need to file for AC21 to USCIS before you change your job.

I-485 Portability (AC21)

http://www.murthy.com/news/UDac21qa.html

http://www.uscis.gov/files/pressrelease/For Permanent Worker Visa, you can have a company sponsor you. How long does the sponsorship have to be?
That is a very good questions many of my associates have come across this very thing. If you can get on with Federal Contractors like Blackwater , Burns , CSC, and Dyncorp etc. the corporate lawyers can help with that. Also check at Embassies in Latin America for further clarification. The Buenos Aires consulate is a very good one to work with in SA.