Boxer, I am AFANG enlisted and just completed college and am applying to Navy OCS to fly. If you want to get out of your contract, you must get a conditional release and have it signed by your commander. Your commander will make the call whether you will be able to be released prior to your contract. Mine was cool and had no problem with it (I have served nearly 6 years of my 8 year contract). The agreement that I signed was for 6 years, to include a min. of 3 years from the last date I used the state tuition assistance. I had no signing bonus.
If you used ANG benefits for school, you will have to pay back your tuition assistance and G.I. bill kicker (if you were eligible for kicker and used it). I believe the non-kicker portion of the G.I. bill is yours to keep. I don't know what state your unit is in, but I am in MO, and my retention NCO told me this is what happens after conditional release...you will be expected to pay back this entire sum within 45 days. Most people cannot do this and the state expects it. After 45 days, it is sent to the attorney generals office and they contact you to set up a re-payment plan. good luck, let me know if you want me to update you when i go through this process this summer.