Inside the iPhone 5

 iPhone 5 is Thinner,Faster and Lighter:-

A6 chip: It's faster! (duh). Here's a summary of what Apple says. "Up to twice as fast compared with the [iPhone 4S' A5 chip]...The A6 chip also offers graphics performance that's up to twice as fast as the A5."Problem is, Apple doesn't say much beyond that. So, I asked Anand Shimpi from chip review site Anandtech.It turns out that Anand's initial guess was wrong. Based on the performance gains, he initially believed the A6 used an ARM Cortex-A15 design. That's the latest and greatest from ARM, the chip architecture that powers virtually all of world's major-brand smartphones.But in a post on Saturday, he says that's not the case."It turns out I was wrong," he wrote.
"Based on a lot of digging over the past couple of days, and conversations with the right people, I've confirmed that Apple's A6 [chip] is based on Apple's own ARM based CPU core and not the Cortex A15," 
The upshot is that the A6 can't be pegged to any current ARM chip design because Apple has taken design liberties. This approach is similar to what Qualcomm has done with its Snapdragon S4, which isn't based on any particular ARM chip design.The graphics processing unit is less clear but Anand believes it could be using faster Imagination PowerVR SGX543 cores.Another analyst believes Apple is able to balance increased performance with decent battery life because of tweaks done independent of the main central processing unit, or CPU. LTE/4G/3G: Apple makes some pretty impressive claims about battery life. Despite 4G LTE's reputation for sucking the life out of smartphone batteries in short order, Apple says battery life, if anything, is a little better compared to the iPhone 4S.
Internet use: Up to 8 hours on 3G, up to 8 hours on LTE, up to 10 hours on Wi-Fi," according to Apple.That probably has more than a little do with Qualcomm's newest silicon. Apple's A6 is paired with Qualcomm's single-chip 28-nanometer MDM9615 LTE, according to Anand.

"Apple claims support for EDGE, EV-DO, HSPA, HSPA+, DC-HSDPA and LTE. The WiFi gets updated to dual-band 2.4GHz and 5GHz 802.11a/b/g/n, using 20MHz channels Apple can hit a peak link rate of 150Mbps over WiFi".

iOS 5 update, iOS 6 on the way:-

The iPhone 4 shipped with iOS 4, but can now be updated to iOS 5 via iTunes. This update adds things like a new notifications system and management options, iCloud support, and the iMessage messaging system. You can find a full roundup in Everything you need to know about iOS 5.
Apple has confirmed that iOS 6 will be available for the iPhone 4 in the fall. This will bring lots of new features and a new Maps app, Passbook for tickets, and a host of other improvements. A few things, like Siri and FaceTime on your cellular network, will not work on the iPhone 4, however. You can find out more in iOS 6.