Speak with Arch Druid Fandral Staghelm in Darnassus.
Excuse me [class], but I'd like just a moment of your time if possible.
The Cenarion Circle in Darnassus is looking for seasoned adventurers such as yourself to lend them aid in a vital research project. While I do not know the specifics, I can inform you that none other than Arch Druid Fandral Staghelm is spearheading this research.
Please - if you are interested, speak with him directly in the Cenarion Enclave within Darnassus proper.