In the last Retired Military Newsletter, they mentioned discounts veterans are due for cell phone service. They explained it was a requirement included in the Federal Telecommunications Act 1996 Discount to Federal Employees Past and Present. They listed the companies and phone numbers:

Cingular (19% discount) 800-319-6393
T-Mobile (22% discount) 866-646-4688
Sprint (15% discount) 888-788-4727
Nextel (18% discount) 800-639-6111
Verizon (23% discount) 800-922-0204

The simplest way was to go to the local office and show them your ID (or DD Form 214). It is quick & easy.