As for the Army and National guard, they have now waived their requirements and it is possible to enter without a GED. I think there are recruiters that could help you with this.
You want high scores on the AFQT.
The Army allows applicants who is currently enrolled in an adult education or college program, and who further is expected to graduate or attain the required credits within 365 days may to enlist in the Delayed Enlistment Pr...

As for the Army and National guard, they have now waived their requirements and it is possible to enter without a GED. I think there are recruiters that could help you with this.
You want high scores on the AFQT.
The Army allows applicants who is currently enrolled in an adult education or college program, and who further is expected to graduate or attain the required credits within 365 days may to enlist in the Delayed Enlistment Program (DEP).
To qualify for the program, a person must have been out of high school for at least six months, and be able to pass the Army’s physical exam and the Armed Services Vocational Aptitude Battery (ASVAB) test.

The program allows recruiters to enlist a high school dropout, according to S. Douglas Smith, a spokesman for the U.S. Army Recruiting Command. But the enlistee must have the GED before shipping off to basic training. The Army will pay for individuals to attend a course to prepare for the GED test and will cover the cost of taking the GED exam.
http://www.homelandstupidity.u...

I think you have to have a high school equivalent diploma for most branches of the military in North America.