The EEOC has put out new guidance on the interplay between several laws that affect the employment rights of disabled veterans, the Americans with Disabilities Act and the Uniformed Services Reemployment Rights Act.
Both USERRA and the ADA apply in the federal government context as well as in the private sector, although policies under the ADA differ somewhat in that the government policies in the area it generally controls are governed by the parallel, and predecessor, Rehabilitation Act.
The guidance includes issues such as what types of questions regarding disabilities that hiring officials may ask in interviews, what constitutes a disability under the laws, obligations of applicants to disclose their conditions, required accommodations and other issues.
The guidance is here: http://www.eeoc.gov/facts/veterans-disabilities.html