Mike, yes I'm a 2010 grad with Hornet and ramius. I recieved one of the GSP (Graduate Studies Program) from the OR "Department" (Operations Research is actually a combination of the math, management, computer science, and economic departments.) The jist of the scholarship is they send me to AFIT (Air Force Insititue of Technology at Wright-Patterson AFB, OH) for 18 months, and in return I will return at somepoint during my career to teach in one of the four related departments. The number of GSP scholarships vary year to year.
As for grad school in general, it depends on your AFSC (Air Force Specialty Code, aka job). For 61s and 62 (scientists and engineers) it's relatively easier than for say, a pilot, because they'll need the knowledge sooner. Otherwise, you really just have to be endorsed by the scholarship committee at USAFA (mainly based on cumultive OPA). Certain national scholarships are endorsed, such as Draper and JFK. Otherwise, its very rare (but is doable) for you to get grad school purely because you find a place you want to go and apply. You really have to work with Dr. Lavin and get approval.
If you or anyone else has other questions on that later stage, let me know. And i know you know many of the abbreviations, but i figured i'd spell out as many as i could in case other people are reading.