bluetooth with a device that doesn't have bluetooth? heh.
Yamipod is free and designed for this purpose.
Connect the iPod, make sure iTunes doesn't run, and then run Yamipod.
http://www.yamipod.com/main/modules/home/
(Make sure iPod is connected directly to computer, not through hub, for minimum hassles.)
There is instructions in the 'docs' section of that site for copying music from iPod to desktop. Then, once in a folder on your desktop, drag this into iTunes.
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You may want to make sure that in iTunes' preferences, it's set to copy music to your 'music' folder automatically (in advanced tab), and not just keep reading the music from the folder on your desktop. Then you should be able to move the desktop folder to the recycle bin, and still have your music work.