Shelley writes: I followed your instructions and now I’m backing up my iPhone with iCloud Backup. Do I need iTunes at all anymore?

Hi Shelley! Sounds like you’re all set with iCloud Backup, which automatically backs up your iPhone’s settings, messages, photos, and app data whenever your iPhone is charging and asleep.

But here’s the thing: syncing with iTunes on your PC or Mac still has its uses, particularly when it comes to photos, podcasts, and songs and videos that you didn’t buy from the iTunes Store.

First, a little background. Thanks to iCloud, you can now backup your device automatically (click here for details), download (or re-download) any applications, songs, or TV shows that you’ve purchased from iTunes, and share recent photos you’ve snapped on another iDevice by turning on Photo Stream. And if you’re into podcasts, you can download new episodes from the iTunes Store app on your handset.

Do I need to sync my iPhone with iTunes now that I'm using iCloud? (reader mail)

If you have a lot of MP3s that you didn’t buy from iTunes, you’ll need iTunes to sync them to your iPhone.

All well and good, but what about songs and videos you didn’t buy from the iTunes Store? To put them on your iPhone, you’ll need to sync with the iTunes desktop software, either using the white USB cable that came in the iPhone box or over Wi-Fi. (More on Wi-Fi iTunes syncing in a moment.)

But wait—what about that new iTunes Match feature, which will let you store all your music in iCloud? Well, iTunes Match, which will scan your hard drive and “match” any songs it identifies with a high-quality version that you can stream from iCloud (or let you upload any tunes that can’t be matched) sounds like a great service, so long as you’re willing to pony up $25 a year. If you’re not, you’re going to need iTunes to transfer any music you didn’t buy on iTunes from your computer’s hard drive to your iPhone.

And while you can re-download any songs or TV shows purchased from iTunes to your iPhone, you can’t re-download purchased movies—or at least, not yet. So if you bought, say, “Toy Story” from the iTunes Store and it’s on your Mac or PC, you’ll need to sync with iTunes to transfer it to your iPhone. By the same token, if you bought “Toy Story” from iTunes directly on your iPhone, you’ll want to sync with iTunes to transfer a backup to your system.

OK, so what about photos? Well, the Photo Stream feature in iCloud will share a limited stream of recent photos you’ve snapped with all your iCloud-connected devices—meaning you could, say, upload pictures from your wedding album in iPhoto to Photo Stream, then go to your iPhone and save the uploaded images from Photo Stream to a new album on your handset.

Now, the Photo Stream method would probably work just fine if you only wanted to upload a snapshot or two, but if you want to load your entire wedding album into Photo Stream, the process might take hours—particularly if we’re talking large, high-quality photos. A much faster solution (as in minutes rather than hours) would be a quick, wired sync with iTunes. (To manage which photos get synced to your iDevice, connect it to your system, open iTunes, select your device in the left column, and click the Photos tab.)

Last but not least, we’ve got podcasts. While you can download as many podcast episodes as you like from the iTunes app on your iPhone, your iPhone won’t automatically check your podcast subscriptions and download new episodes the way that iTunes does. (Why not? Great question.) If you have your podcast subcriptions all refreshed in iTunes, you might be better off syncing all your new episodes in one shot via an iTunes sync rather than downloading them one-by-one on your iPhone.

Hope this helps, Shelley—and if you have more questions, let me know!

Bonus tip: Thanks to iOS 5, you can now sync your iPhone, iPad, or iPod Touch with iTunes over your home Wi-Fi network, no wires required. Keep in mind, though, that your PC or Mac must be powered on to perform a Wi-Fi iTunes sync. Also, syncing with iTunes over Wi-Fi will take longer—sometimes much longer, especially if you’re trying to sync lots of music or video—than it would using the USB cable that came with your iOS device.

To enable Wi-Fi sync for your iPhone, iPad, or iPod Touch, open iTunes, connect your device and select it in the left column, and check the box labeled “Sync this [iPhone, iPad, or iPod Touch] over Wi-Fi.”