Do I HAVE to restore my iPod?

My friend gave me his iPod as a present and I love all of his music. But his iPod is compatible with Macintosh and I have an Toshiba. It says to be able to play with it on iTunes I have to restore it to be compatible with my Toshiba. Will this erase all of the music/pictures on his iPod? Is there any way to transfer the music onto my computer then restore it all (maybe put it on a jump drive or something)?