libgpod4, gtkpod, ifuse, usbmuxd
After having installed the above packages
sudo mkdir /media/iPhone (you can choose whatever location you desire) sudo chown `whoami` /media/iPhone ifuse /media/iPhone (this will mount your iphone on /media/iPhone) mkdir -p /media/iPhone/iTunes_Control/Device sudo lsusb -v | grep iSerial
this will output like something this:
ipod-read-sysinfo-extended 8372189bcafb324324eafbs8432b4235b32130537 /media/iPhone
check if /media/iPhone/iTunes_Control/Device/SysInfoExtended now exists
launch gtkpod and follow the on-screen instructions. If it shows any warnings don't worry too much ;)
You should now be able to access your iphone playlist and add songs.
After doing anything you want don't forget to "save changes" on gtkpod and quit normally
Then before unplugging your iphone always remember to unmount it using
fusermount -u /media/iPhone.
From now on you can mount your iphone with
synchronize it with gtkpod and unmount it with
fusermount -u /media/iPhone