Pretty Little Liars!!!

Just started watching pretty little liars last week and im onto season 2 episode 6.. do you actually find out who A is or is is an ongoing thing?! A has been everyone i have seen on the programme in my head and now im wondering who the real A actually is but dont know if you actually find out.. ps if you know please dont tell me but feel free to leave theorys if you havnt found out who it is yet!! Im hoooooked on the programme!