Okay so I'm having major issues installing/running iTunes through Wine, but I'm in major need to create (and be able to restore from) a full, complete backup for my iPhone since I'm doing a ton of tweaking to it. I don't really know what I'm doing, so there's a 110% chance I'm gonna screw it up, but hey, no one ever learned anything about technology without crashing it a good 100 times right? =P
It's more recommend to create a VM and install iTunes on it, so that you can perform a full/complete backup.
To create a VM, there is a official doc via wiki: https://help.ubuntu.com/community/VirtualBox.
Another discussion: How to install Windows 7 inside Virtualbox of Ubuntu?
Hope this can help you.