Just been through the process myself. Basicly it involves filling in a fairly lengthy form for AA, they then select people to put forward to Easyjet. You fill in a stardard Easyjet form and bring it to a recruitment day at EasyLand in Luton along with people joining directly with EasyJet. Not sure about wether it was just a formality, as we went through the process as everyone else and weren't separated.
If you're sucessful you go through to a 4 week mon-fri course at Luton (EasyJet pay for your accomadation thoughout this). Before working till 31st October with EasyJet.
All credit to the staff, they said they wanted to try and make people feel at ease and have fun and they certainly managed to do that during the day.
If you'd like anything more specific feel free to drop me an email.