I checked in during the first week of June and I classed up today.  You have to have completed BOLTC, get your upchit, PRT and do IFS before you can class up.  When I first checked in, people who requested Corpus classed up sooner because they needed more people.  Right now it is equal with both Corpus and Whiting each accepting 6 guys at a time.  Once you complete the requirements its a matter of making sure Flight Management knows you are set to class up and where you want to go for Primary, and then just waiting.  I was told today that things are filling up fast and they are going to stop sending people here for a few months to let things smooth out.