Late Tuesday night, Apple released version 2.1 of its iPod touch firmware.

According to AppleInsider, the update is available through iTunes and adds many of the features found in the newly-released second generation iPod touch handsets that aren't dictated by hardware improvements.

Such changes include the "Genius" feature, which can automatically create playlists of related music, software-related optimizations to improve battery life and assorted bug fixes.

Apple has yet to post a full list of specific updates for the 2.1 version, though the software is a free upgrade for any iPod touch owner using version 2.0 or later of the firmware; those using version 1.x of the firmware will need to pay a US$9.99 fee to procure the 2.1 update.

The current readout reads as follows:

The version 2.1 update for iPhone and iPhone 3G users will be free but will appear slightly later, launching on Friday.

If you've had a chance to play with the version 2.1 firmware, let us know what you think over in the comments or forums.