I’ve been seeing this often lately in TBL, where fellows clerics announce their “heal” or “ausrine statue” timers with this macro, how do you do it ?
Seems it uses the "!! " thing but I don’t know much 
It’s an addon: Cooldown Tracker or cdtracker
Once you have the addon, activate chat for the skill you want to display.
Also you can play a message that would be displayed when you cast the skill.