Classes open for trial its:
Druids: 1-2 Resto
Hunters: Closed
Mages: Closed
Paladins: 1-2
Priests: 1-2 Holy
Rogues: Closed
Shamans: Closed
Warlocks: Closed
Warriors: 1 Prot and maybe a GOOD fury
Even if your class is closed feel free to make an apply, it can be recognized after some times when a spot for a class get's open.