Leap Wireless announced on Thursday morning that its Cricket prepaid wireless carrier will begin offering the "first" prepaid iPhone option in the US on June 22. Though the devices will cost significantly higher up front than iPhones purchased "on contract" from another carrier, Cricket offers a $55 per month, no-contract plan which includes "unlimited" calls, texts, and data.

Potential customers will be able to buy an 8GB iPhone 4 for $400, or a 16GB iPhone 4S for $500—a bit less than the no-contract phones offered by AT&T. But unlike AT&T, Cricket's monthly plan is prepaid, a benefit for those with less-than-stellar credit, or those who don't want to be locked in for two years to a single carrier. Since Cricket's network is based on CDMA, however, you must buy an iPhone directly from them to use their service. (It's possible the the iPhone 4S could be moved to a GSM-based network later using a SIM card, however.)

Some in the Twitterverse have already expressed disappointment that Cricket won't be offering an even cheaper prepaid iPhone in the form of the 3GS. Apple never produced a CDMA version of the iPhone 3GS, however, so such a product wouldn't make sense to create just for Cricket's prepaid market.

Still, Cricket's $55 per month plan for the iPhone 4 and 4S is a pretty good deal, offering unlimited call and texts. But Cricket's "unlimited" data isn't actually unlimited, of course; after you go through 2.3GB, your data will be throttled. At the same time, 2.3GB is more than many customers will use in a month—AT&T has claimed in that past that only a small percentage use more than that in a month on its network. If you're the type to avoid streaming video and tons of audio, you'll probably be fine, though we have heard from heavy streaming media users that they often butt up against their data limits on AT&T.

Cricket offers a form for those interested in an iPhone to sign up and received e-mail alerts when June 22 approaches.

It's worth noting that there is another way to get a "prepaid" iPhone 4 or 4S, however. You can buy a prepaid AT&T-compatible microSIM from StraightTalk, an MNVO run by TracFone and Walmart, for just $15. StraightTalk offers a $45 monthly plan that also includes unlimited calls, texts, and data. And since StraightTalk runs over AT&T's network, you don't even need an unlocked iPhone—just pop in the SIM, update your APN data settings, and you're good to go.