It turns out that there is another good software :
This is for backup, transfer of iPod songs. But looking harder I notice there WAS iFree which actually can move songs between devices. But of cos Apple shut them down.
Well, according to my friends, you will not run into problem as long as you keep your songs in MP3. The M4P formats has DRM. Well, thats life. Though you could run away from MP3 right? Well, I did too when I was using WMA, but tough luck when I got my K750i, has to change all back to MP3.