Senuti is the tool you use to turn your mac into an iphone dock. It will play and copy music.

Senuti — Recover music from your iPod, iPhone or iPad to your Mac.

Ipoddisk turns your ipod into a disc device on which you can find your music and copy it

Ipoddisk

Iphone Explorer allows you to browse the files and folders as though it was a usb flash drive

Iphone Explorer