iTunes option to fit more songs on your iPhone/iPod - Marco Arment

iTunes option to fit more songs on your iPhone/iPod - Marco Arment

I noticed this when it first appeared (not sure when) and have been using it ever since. Highly recommended.

If you only buy music from the iTunes Store (at 256kbps), this effectively doubles the capacity of your device. For music from other sources, it will vary depending on the import settings, but there is likely to be some improvement.