Q: transferring Itunes account from XP PC to Windows 7 PC

My ITunes account has been on an XP machine for several years.  I now have set up a Windows 7 machine to ab able to access the newest version of ITunes which will not install on XP.  The Windows 7 PC is authorized.  Can someone walk me step by step how to transfer the music files from the XP computer to the new Windows 7 computer?