If you're iPod or iPhone is near full and you're not able to get any more music, videos or anything else on it, don't despair. Here's a way to reclaim some space. And all you have to do is sync... a little differently.
iTunes 9.1 has a new feature that reduces the size of your music.
A great majority of music on the iTunes music store is digitized (encoded) at a bit rate of 256 Kbps. The new iTunes feature reduces music in size by converting music files to 128 Kbps. The hearable difference between the two bit rates is so subtle that you would be challenged to hear a difference at all, even with really, really good headphones. (Really, if you can hear a difference, you're not happy listening to music at 256 Kbps either.)
Launch iTunes and connect your iPod or iPhone (or iPad). Toward the bottom of the Summary screen in the Options section, check the option "Convert higher bit rate songs to 128 Kbps AAC". Now, whenever you sync, music (the music being synced) with be converted to a smaller 128 Kbps size and transferred to your iDevice. The music in your iTunes music library (the originals) are unmodified.
Please note that the first sync after you've turned this feature on may take a long while, depending on how many songs need to be converted.
We tried this feature on an iPhone that had 1,395 songs totaling 6.51 GB in size. We started the sync. A few hours later, 757 songs were converted. (The rest were already at 128 Kbps.) The new total size of all the songs? 5.35 GB. That's 1.16 GB reclaimed!