My dad is a long time Marine (24+ years) and I was in the AF from 73 to 77. He gets a lot of military related emails and forwarded me on the news about this. I was able to sign up for online access to the exchange stores. Here's the blurb and link:
Veterans can now verify their online shopping eligibility at VetVerify.org. The Exchanges are also accepting some veterans as beta testers before opening the doors to all veterans. See updates below for more information.
I was verified and also selected to beta test. Still looking around the sites to compare prices and such.