This took me AGES to figure out, so let me share the knowledge!

1. YOU CANNOT DRAG FROM THE LIMEWIRE TO I-TUNES (as you may have figured out already )

Your limewire tunes/films should be saved to a folder on your PC, mine is in a folder called "Shared", I don't know if it is the same for everyone or not. Locate where your files are (shouldn't be too hard, they WILL be saved under the users' folder unless you have selected otherwise.
Once you know where they are, select the option "add file to library" from the File button i i-tunes and bring up the folder with your limewire music in. Select one, and open it. It will automatically go into your library. This is VERY tedious if you have a lot of music, but well worth it.
Can also be used to put movies onto your i-pod, but make sure that they are in the i-pod format. If they are not, then on some you can open into your movies part and you can change it (select convert selection to i-pod/i-phone) and it can then go onto your i-pod/phone.

Hope this helps, feel free tp PM me if you're having trouble.