Is there a proper way for me to convert my PC formated Ipod to use with a mac instead? Do I just need to reformat the Ipod when connected to my PC, then add the music again via my mac? Also, what happens to the 100+ songs I purchased on Itunes via my PC? Do I just need to enter my Apple ID and password and they will show up on my mac? I have the songs I purchased backed up on an external. Do I need to add them manually to Itunes? (Along with the rest of my music).