Cricket Wireless announced, Thursday, that it will begin offering the iPhone 4 and iPhone 4S with its prepaid wireless plans. Pre-orders will begin on June 15, and prepaid iPhones will go on sale on June 22, making Cricket the first wireless carrier in the U.S. to offer the iPhone with a prepaid plan.

Historically, major wireless carriers have sold the iPhone only with two-year service contracts. An 8GB iPhone 4 typically sells for around $99 with a contract, and a 16 GB iPhone 4S typically sells for about $199. Monthly charges average $60 to $80, and most major carriers place caps on data use. 

iPhones sold with major carrier contracts are typically "network locked" so that the phones can be used only on that carrier's network. Some iPhone users have resorted to "jailbreaks" to remove this limitation so that their iPhones can be used on other networks.  Apple cautions users that some types of "jailbreaking" can void the phone's warranty. Mobile customers who want an iPhone with no contract can buy an unlocked version of the phone directly from Apple, at $549.99 for an iPhone 4 and $649.99 for an iPhone 4S. 

Cricket is poised to offer a less expensive contract-free iPhone, charging $399.99 for the iPhone 4 and $499.99 for an iPhone 4S. This is still more expensive than purchasing an iPhone from a major wireless carrier with a contract, but for some of Cricket's 6.2 million customers, that cost may be offset by pay-as-you-go plans and Cricket's lower monthly charges.

Cricket iPhone customers will pay $55 a month for unlimited calling and texting.  Nominally, the plan also offers unlimited data, but Cricket's "fair use policy" slows connection speeds to 56 Kb per second if monthly use exceeds 2.3 GB.