Apple chief executive Steve Jobs today unveiled the "iPhone 4," at Apple's Worldwide Developers Conference (WWDC) in San Francisco. 

"We are going to take the biggest leap since the original iPhone," said Jobs in a keynote speech . Jobs said the iPhone 4 includes many new features including a front-facing video camera to allow for video-conferencing, a better still camera, improved battery life and a screen with higher resolution. 

Let us have a quick look at key "iPhone 4" features.

• Retina display: 3.5-inch (diagonal) widescreen Multi-Touch display, 960-by-640-pixel resolution at 326 ppi
• Size and weight - Height: 4.5 inches (115.2 mm), Width: 2.31 inches (58.6 mm), Depth: 0.37 inch (9.3 mm), Weight: 4.8 ounces (137 grams)
• Video recording, HD (720p) up to 30 frames per second with audio
• 5-megapixel still camera
• Three-axis gyro, Accelerometer, Proximity sensor, Ambient light sensor
• Talk time: Up to 7 hours on 3G, Up to 14 hours on 2G
• Standby time: Up to 300 hours
• Internet use: Up to 6 hours on 3G, Up to 10 hours on Wi-Fi

For connectivity, iPhone 4 supports UMTS/HSDPA/HSUPA (850, 900, 1900, 2100 MHz) & GSM/EDGE (850, 900, 1800, 1900 MHz) along with 802.11b/g/n Wi-Fi (802.11n 2.4GHz only).

"iPhone 4" also supports Multitasking. The multitasking user interface allows you to quickly switch between recently used apps.

FaceTime a video calling feature introduced in "iPhone 4" works over Wi-Fi only. This feature is not available for 3G, Apple might have taken AT&T's stressed 3G network in consideration however it might change with 4G/LTE iPhone. We may have to wait another year for that once AT&T launches comercial LTE network in USA market.