"The Locrian squadrons nor the javelin wield
Nor bear the helm nor lift the moony shield
But skilled from far the flying shaft to wing
Or whirl the sounding pebble from the sling
Dextrous with these they aim a certain wound
Or fell the distant warrior to the ground"
Iliad book xiii line 891
So it seems they were archers and slingers without the crescent shield and javelins of the peltast. It is interesting to see how the concept of the sound of a flying slingstone has survived the translation. I wonder what a more literal translation would come out like?
(EDIT) Already discussed here
http://slinging.org/forum/YaBB.pl?num=1146851361