I'm using 7.6 and all you have to do is convert the files to acc then find the file on your drive and then change the .m4a to .m4r and then point itunes to that folder and it should transfer the file to the ringtones folder and it should show it in your ringtones list
If your running a WinPC....just download a program called "Iringer" (google it, its free).
The program will allow you to take a song, cut what you want out of it and then it will AUTOMATICALLY put it into your ringtones section of Itunes!
All you have to do is sync.