The only 2nd job change for gunners released so far is Launcher -> Blaster and they get Spectral Eye and Sattellite Beam
Spectral Eye = shows an arrow w/ enemy name for all enemies off screen in dungeons (just like enemy players in PVP)
Sattellite Beam =
http://www.youtube.com/watch?v=R84wFE_wXaE
dunno what the other 3 classes will get yet :E
edit: Blaster job change is at level 48 so I assume that'll go for everyone