Rights of Employees Serving in the Military and Rights of Employers who Employ Them
The Uniformed Services Employment and Reemployment Rights Act (USERRA) was enacted by the U.S. Congress in 1994 for three purposes:
1.  To encourage non-career military service (National Guard and Reserve);
2.  To minimize disruption to service members and employees; and
3.  To prohibit discrimination because of military status.
The U.S. Department of Labor has excellent resources on the Internet. Here are links to some of them:

USERRA applies to all employers and all employers must have the USERRA poster posted in a place where employees and job applicants can see it. This poster is at:  http://www.dol.gov/vets/programs/userra/poster.pdf

For general information go to:  http://www.dol.gov/vets/

The main website for USERRA is:  http://www.dol.gov/vets/programs/userra/main.htm

A special USERRA Advisor for both employers and employees is at:  http://www.dol.gov/elaws/userra.htm

An interactive design for employees and employers is at:  http://www.dol.gov/elaws/vets/userra/mainmenu.asp

The State Bar of Arizona's Arizona Attorney has an article in its October 2005 edition that gives a good overall description of USERRA. It can be found at:  http://www.myazbar.org/AZAttorney/PDF_Articles/1005DayJob.pdf