Beginning on Sunday, Sprint will offer an alternative to prospective iPhone customers who want to avoid service provider AT&T's considerable monthly charges. The ZTE Peel is a "combination case/cradle" that users can slip onto the back of an iPod touch to gain many of the data benefits of the iPhone — with a few important caveats. Is it worth it?

How does it work?
It's simple: Slipping the Peel onto the back of an iPod touch converts the device into a 3G mobile hotspot, as well a 3G radio. Currently, iPod touch users can only access the internet if they're within range of a Wi-Fi network; with the new case, the device creates its own Wi-Fi.

What's the attraction?
Customers who don't want to pony up for an expensive contract with AT&T can pay significantly less to get online. The Peel costs a mere $79 and requires a $30 monthly data plan; with those not-unreasonable prices, the Peel may be attractive to customers who fantasize about "telling AT&T what it can do with its $65-per-month-minimum-not-including-taxes-or-texting two-year contract," says Rick Broida at CNET.

What's the downside?
Standard iPhones are not known for long battery lives, and the Peel — with a three-hour limit — is worse. Plus: While the Peel works with older iPod touch models, it's not compatible with Apple's most recent version. And, of course, you're not actually buying a phone, says David Chartier at Macworld, so you'll still have to "resort to third-party solutions like Google Voice and Skype" for phone and texting needs. Perhaps most importantly, Sprint imposes a 1-gigabyte data cap, inadequate for many users. On the bright side, says Wilson Rothman at MSNBC, you'll be able to fool at least some people into thinking you have an iPhone."

Sources: L.A. Times, Macworld, CNET, MSNBC