On 24th June, 2010 Apple released the new generation's iPhone 4 which according to Apple is the most evolved model compare to the previous versions. Some of its salient and improved features are as follows:
Retina Screen:This is highest-resolution and sharpest phone screen ever with a resolution of 640 x 960 at 326 ppi so your eye is unable to distinguish individual pixels.
Sensor: It has 6 sensors, including 1 gyroscope sensor so it will benefit cooler game and application.
Better LED Flash for Camera:It's camera is 5 megapixels which might also photograph the high definitions (720p) videos. In addition Apple promotes a new video editor called iMovie app. This hi tech camera helps to captures amazingly detailed images.
New MultiTasking O.S. and Folders:The biggest improvement of iPhone 4 is its multitasking support with new operating system iOS4 means it can handle multiple applications simultaneously and you can switch between them instantly. Provision of folders is the great function added which is a new way to organize the apps.
Stainless steel antenna and new H/W added components:iPhone 4 uses A4 processor for quicker speed than other phones. An additional microphone at the top and few internal adjustments will help to get clearer voice conversation.
Better Battery Life:Life of 300 hours but ten hours of web browsing, ten hours of video, fourteen hours of 2G talk time and 40 hours of music is possible with the new battery.

Now comes on to Apple iPhone 3GS which is better and is technically twice as faster as compared to previous version iphone 3G. Some of its salient features are real 3D gaming experience, more memory storage, improved connectivity for faster download(Apple iphone 3GS supports HSDPA(high speed data packet access) downloading, capable to fasten the downloading speeds upto 7.2 Mbps), better camera(this iphone has inbuilt 3 MP camera with video recording support at 30 fps and VGA ( 640 X 480 ) resolution), digital compass, voice control, better long lasting battery and nike+ support(nike + support with water and oil-proof finish provides powerful and comfortable in-line remote control on the headphones which allows you to shuffle and change tracks and volume on the go).