I am a full-time graduate student with an F-1 visa, but I would like to find a job with international organizations such as the UN, or other non-government organizations in the U.S. I currently have a master's degree, but decided to discontinue my study. My student status is valid until June 2009, so I'm trying to find a job before then so that I can legally stay in the U.S. and transfer my visa status.
The ideal time line is to find a job asap, get a valid visa, and submit my withdrawal to graduate school before June.
Note: All my questions below are in condition that I find a proper job and get all necessary support for my visa from my employer
1. In this case, is it correct to apply for G-4 visa, or B-1 visa? Is there any distinction between employees in the U.N. and those in other non-government organizations as regard to proper visa to get, or all the case fall to G-4 category?
2. Is there any time restrict such as in an H-1B, say applying by April 1, but able to work only from October? I heard that in H-1B case, if applicants cannot maintain their status legally from April to October, they have to go back to their original country and come back in October.
Is it also okay to start working right after I get a proper visa issued, not waiting until October as is the case with an H-1B?
3. I would like to stay in the U.S. while my visa status changes so that I don't have to return my country in the meantime. Is it possible to change visa status to G-4 without visiting my home country?
Thank you very much for your help in advance!!

