While lucky iPhone owners get their 2.1 firmware upgrade for free on Friday, even luckier iPod touch users can grab it right now, although they do have to pay that pesky fee of $9.95 for it. Still, it is worth every penny, especially if you're upgrading from 1.x firmware.

As most users have already found out, iPhone and iPod touch OS 2.0 includes the App Store. Later versions include the application marketplace too, as does iPod touch software 2.1.

“The App Store offers applications that take advantage of the groundbreaking technology in iPod touch, such as the Multi-Touch interface, the accelerometer, real-time 3D graphics, and 3D positional audio,” Apple reveals. “With just a tap, download games, social networking, sports, travel, and more applications directly onto your iPod touch over a Wi-Fi network and start using them right away,” reads Apple's concise description of the application venue released at the same time with the iPhone 3G.

Still, the biggest reason why iPod touch users should really consider upgrading to 2.1 software is the new Genius feature Apple introduced yesterday at the Let's Rock event. Apple best explains this feature by offering a concrete example, saying that if you’re listening to a song you really like, and want to hear other similar tracks, all you have to do is hit the new Genius button and the new (Genius) algorithms find the songs in your library that “go great” with what you're currently listening. The playlist can be saved to play it later, or refreshed, for new results.

Other great stuff brought by the 2.1 software update for iPod touch users includes Push Email through Microsoft Exchange ActiveSync, updated Keyboard and Dictionary support, and support for MobileMe, a new service that keeps all your information up to date on every device you use, among others.

Evidently, by upgrading from 1.x firmware on your iPod touch, you also get the new features added in the January ’08 update. Those include Maps, Mail, Weather, Web Clips, and a customizable Home screen.

Interested? Here it is (requires an iTunes Store account).