A pair of Apple patent applications show the company is constantly working to keep the iPod ahead of the evolving digital music game.

Macsimum News notes that one patent (filed in December 2004 but published yesterday) describes a fully wireless-enabled iPod, but describes the device as a "portable shopping cart".

The patent posits a device that's capable of connecting to a store using mobile phone networks or WiFi networks.

The device described in the filing offers one or more speakers, a microphone, headphone jack, a FireWire or USB port, flash memory slots, and "one or more antennae or ports used to connect to a local networks".

This patent discusses a method of tagging a digital file, such as a song, ringtone, video or PDF (perhaps available on iTunes) using one device (perhaps a mobile phone) for download later to a Mac or PC.

A second patent describes a system to automatically create audio navigation tags for an iPod.

These tags are created from the metadata associated with a song, so could include artist and song name, playlist or genre, for example. This metadata is converted from text to speech and transformed into small audio files, which can be used to offer information to help a user navigate their collection without using the iPod's display.