'usbmuxd' stands for "USB multiplexing daemon". This daemon is in
charge of multiplexing connections over USB to an iPhone or iPod
touch. To users, it means you can sync your music, contacts, photos,
etc. over USB. To developers, it means you can connect to any
listening localhost socket on the device.

WWW: http://marcansoft.com/blog/iphonelinux/usbmuxd