College degree, less than 30 years old, pass a military physical including better than 20/70 correctable, score well on AFOQT, and find a unit that will take you.
Factsheets : PILOT REQUIREMENTS & QUALIFICATIONS
My impression is that it is a lot more competitive than getting a regular active duty AF UPT slot, but I think the rewards are worth it. There are a fair number of units hiring right now, if you don't care about geography or airframe. Also look at the Air Force Reserve, and maybe Army National Guard if you're interested in Helo's.