Apple's latest smartphone iPhone 4S hit stores on Friday and smashed previous debut weekend sales records as the technology giant sold over 4 million units.

You can buy iPhone 4S at these 6 places:  Apple Store, AT&TVerizon, and Sprint, Sam's Club (The memberships start at $40 a year), Radio Shack, Target, Best Buy.

iPhone 4S has the same exterior design as iPhone 4, such as glass back and 3.5-inch retina display, but it has some amazing features under the hood. Start the slideshow to learn about each of them.