Hi Jeffrey! Excellent question—and indeed, it’s one my wife and I had to tackle with our own iPhones.
As it turns out, you don’t need the same iTunes Store account to share photos using Photo Stream—but you will need to share an iCloud account.
First, a little background for those who aren’t familiar will all things Photo Stream. One of the key features in Apple’s new online iCloud service, Photo Stream tries to solve the problem of syncing photos between your various iDevices.
Once you have Photo Stream set up, you can take a picture on your iPhone, and it will automatically (and wirelessly) appear on your iPad, your Mac, or any other device that you’ve connected to your iCloud account. (Yes, Windows PCs will work with iCloud, but not Android phones or other smartphones with names that don’t begin with a lowercase “i”.)
But while Photo Stream will sync photos between your various devices, it isn’t intended to be a social photo-sharing service; in other words, there’s no way to “subscribe” to someone else’s Photo Stream.
In practical terms, that means anyone who wants to share their Photo Stream with someone else will also have to share their iCloud account—a cozy arrangement that’s probably better left only for immediate family members or the closest, most trusting of friends.
So, here’s how it works in my family. I have an iCloud account that both my wife and I share; if you go to Settings, iCloud on my wife’s iPhone, you’ll find the Apple ID for my iCloud account. And since we both have Photo Stream enabled on both our handsets, any picture that one of us takes on our iPhone will, a few seconds later, pop up in the Photo Stream folder of the other.
What about the email, contacts and events in my iCloud account? Well, my wife and I share our contacts and calendars, too, although not email (she uses her own Yahoo! Mail account, while I use Gmail).
Now, my better half and I could use the same iCloud account without mingling our calendars, contacts, and mail; all you have to do is switch those features off in the iCloud settings on our iPhones. However, you can’t prevent someone who’s logged into your iCloud account from sharing your mail, calendars, and contacts. It’s something to keep in mind before you starting letting all your friends log into your iCloud account for the sake of Photo Stream.
Remember, too, that once a photo is shared through Photo Stream, it’s not easy to unshare it—meaning that if you accidentally snap a picture of a surprise holiday gift for your wife (and yes, there are other scenarios I can imagine that aren’t quite as sweet), you won’t be able to delete the snapshot from her phone unless you turn off Photo Stream manually on her iPhone. Update: Thanks to a recent iOS software upgrade, you now can delete individual pictures from Photo Stream. Read this article for more details.
OK, so what about your iTunes Store account? Well, this is where it gets (more) confusing.
If you’re new to all things iPhone and iTunes, it’s possible to sign up for a single Apple ID that will sign you into iCloud and manage your iTunes purchase. But many of us longtime iPhone users have, over the years, ended up with different Apple IDs and iTunes Store accounts—and no, you can’t merge them.
That said, you can sign in to iCloud and the iTunes Store using different accounts on a single iPhone, iPad, or iPod Touch—and that means you and your wife could, theoretically, use different iTunes acccounts on your phones while still sharing an iCloud account (and, hence, Photo Stream).
Of course, whether you and your wife actually want or need different iTunes accounts is another question; my wife and I, for example, happily share an iTunes account, all the better for sharing purchased apps, music, and videos.
Bottom line: yes, you can share Photo Stream with someone else, but only if you share your iCloud account too—and you probably shouldn’t share your iCloud account with just anyone.
Still have questions? Let me know!