Resolved Question: How to convert Ipod 30gb to MP3 Player without losing the songs and videos on it?

I bought an Ipod 30gb from a buddy of mine which has a ton of songs and videos that I want to keep. All of them were purchased through itunes or burned from his CD's. He has since purchased a later version Ipod. When I plug the Ipod into my computer it logs into his account and asks me to delete the content on the ipod. All i want is to keep the songs that i have on it currently and add some of my own music from my CD's / MP3s. How can I go about doing this? Will my collection still be categorized and easy to locate on the ipod if I convert it?

THANK YOU!