In a first for US wireless carriers, Sprint and Verizon Wireless will allow iPhone 4S customers to unlock their mirco-SIM card slots, which enables use on wireless networks around the world ...

Contrary to initial reports, the Sprint version of the iPhone 4S will not come with an unlocked microSIM slot allowing customers to pop in international SIMs; it will be able to roam on ...

In contrast, Verizon and Sprint can offer the iPhone 4S with the GSM micro-SIM slot unlocked for international use because the companies use the CDMA standard in the United States.

Sprint is in advanced testing of an iPhone, possibly for sale this fall, that would run at first on a 3G wireless network rather than Sprint's faster WiMax, according to recent reports.

If you factor in the cost of the $199 iPhone 4S, over two years you'd pay $1,896 on Sprint, versus $2,520 on AT&T and $2,640 on Verizon.

Misek’s research note said the iPhone 4S will support Sprint and T-Mobile, finally bringing Apple’s smartphone to all four major U.S. carriers.