Need help with ipod nano 3g

Ok so i just got a ipod nano 3g and i connected it to windows and saw that it was seen as a removable drive and it said inorder to use it i had to format it so i did and now i cant use it on my mac it sees it as a flash drive thing and doesnt come up n itunes please help!!!!

same thing is happening with my pod. got a new one last week but if at all I could fix it I'd be over the moon