QUOTE(YuAndDan @ Jan 1 2007, 01:05 PM)

The rules for naturilization to become a citizen can be found here:
http://www.uscis.gov/files/article/M-476_English.pdfFor a spouse the rule is 3 years 18 months, with periods ounside the USA of no more than 6 months.
The exemption for non profits has to do with non-profits that promote the USA.
You will need to obtain a re-entry permit if you plan on being away from the USA for longer periods of time.
See:
Now That You Are A Permanent ResidentYuAndDan, read Section 319
SEC. 319. [8 U.S.C. 1430]
(a) Any person whose spouse is a citizen of the United States may be naturalized upon compliance with all the requirements of this title except the provisions of paragraph (1) of section 316(a) if such person immediately preceding the date of filing his application for naturalization has resided continuously, after being lawfully admitted for permanent residence, within the United States for at least three years, and during the three years immediately preceding the date of filing his application has been living in marital union with the citizen spouse, who has been a United States citizen during all of such period, and has been physically present in the United States for periods totaling at least half of that time and has resided within the State or the district of the Service in the United States in which the applicant filed his application for at least three months.
(

Any person,
(1) whose spouse is
(A) a citizen of the United States,
(

in the employment of the Government of the United States, or of an American institution of research recognized as such by the Attorney General, or of an American firm or corporation engaged in whole or in part in the development of foreign trade and commerce of the United States, or a subsidiary thereof, or of a public international organization in which the United States participates by treaty or statute, or is authorized to perform the ministerial or priestly functions of a religious denomination having a bona fide organization within the United States,
or is engaged solely as a missionary by a religious denomination or by an interdenominational mission organization having a bona fide organization within the United States, and © regularly stationed abroad in such employment, and
(2) who is in the United States at the time of naturalization, and
(3)
who declares before the Attorney General in good faith an intention to take up residence within the United States immediately upon the termination of such employment abroad of the citizen spouse, may be naturalized upon compliance with all the requirements of the naturalization laws, except that no prior residence or specified period of physical presence within the United States or within a State or a district of the Service in the United States or proof thereof shall be required.