I'm certain many of you have found that due to Apple's lack of support for Linux, those of us who use Apple products are having large headaches.
I have found a work around to get music, podcasts, and video on to your iDevice.
Disclaimer: I am not responsible for any damage done to your device.
If you have attempted to sync via an application like Banshee or Rhythmbox, your library will most likely have become corrupted. We need to fix this before going further.
Navigate to your iPhone in the file manager on Ubuntu.
Delete the folder "iTunesControl" and reboot your iDevice.
In cydia on your jailbroken device, search for Bridge and install it.
Back on Ubuntu, make a folder in your iDevice label it something you will remember. You will drag and drop your music here.
In Bridge, click on the files icon at the bottom of the screen. Point the browser to /private/var/mobile/media/ ( it may appear as "User" in blue) your folder should be in here. Open it and select the music you want to import.