is it safe to use my samsung intensity 2 wall charger for my ipod touch?

[K.K. Nest]

i just bought my new 4th gen ipod touch and i thought it would be smart to plug in the usb cord to my samsung intensity 2's usb slot for the wall charger so i could charge it without a computer. however i wasnt sure if the voltage was too high or the ipod would get fried. i kept it in over night last night and nothing happened besides getting warm. just wondering if it was safe for prolonged use