Nomally iTunes and Ubuntu is a no-go, however using the latest wine from the Ubuntu it is possible out of the box – I’ really impressed of the wine project.
What you need
Check that you got the at least the following wine version:
$ dpkg -l | grep wine | awk '{ print $2, " ",$3}'
wine 1.1.29~winehq0~ubuntu~9.04-0ubuntu2
wine-gecko 1.0.0-0ubuntu1
If not, then install wine:
$ sudo aptitude install wine wine-gecko
Then download iTunes 8.x (important to download version 8.x otherwise it doesn’t work out of the box)
$ wget wget http://appldnld.apple.com.edgesuite.net/content.info.apple.com/iTunes8/061-6717.20090715.XsE4R/iTunesSetup.exe
Then just run the install process
$ wine iTunesSetup.exe
And finally start iTunes.