Eurogamer: Advanced Classes, Hands on, Video
The Galactic Struggle: Hands on, Interview with Jake Neri
Strategy Informer: Interview with Daniel Erickson
Gamespot: Hands on, Interview with Daniel Erickson
VG247: Interview with Jake Neri
Edge Online: Interview with Daniel Erickson
As a caveat, you might want to read our class speculation article and the chart we made back in December.
Update: New high quality version of the Advanced Classes:
...each Advanced Class will have a further three branches of skills to specialise in (equivalent to World of Warcraft's talent specialisation options on a single class). The first two skill trees are particular to your Advanced Class, while the the third is a shared set of skills which expand on the core abilities of the main class. (Eurogamer)
Note: We will add other articles about the press event as we find them.