Ubuntu 10.04 LTS supports iPhone/iTouch Playback, Though so far syncing is not completely working (atleast for me). But you can delete songs from your iPhone/iTouch. All you need to do is install “Amarok” music player from Ubuntu software Center. Although Rhythmbox detects and plays iPhone/iTouch songs but doesn’t allow you to modify the contents.Here are the steps to delete songs from iPhone/iTouch on Ubuntu:
Plug in the iPhone and launch Amarok Music player.

You will see your iDevice on left pane. By default all songs are grouped by Artist.

Select the song (expand the artist), right click on it and select “Delete Track” and you will be prompted for confirmation, click on delete button.Now you will see “Sync in Progress” on your iDevice screen just like when you sync it with iTunes.Thats it your song is deleted.Here is the video that I did on this:

iphonehelp.in