Speed
Guess what "S" stands for? Yes, that's right; "S" stands for speed!
According to Apple, the first thing you'll notice about iPhone 3GS is how fast it's applications will launch. Web rendering will happen in a fraction of time and you can view your email attachments much faster. The iPhone 3GS has a built-in processor which is two times faster than the previous generations and it's more responsive than iPhone 3G. Although it's much more faster than the previous models, it consumes less which has an impact on the improved battery life.Camera
This is one of the strong points of iPhone 3GS. With an increased resolution 3-megapixels auto focus camera (30 frames per second VGA),
your shots will have a much better quality under any condition. With a tap, your shots will be saved in Camera Roll. From there, you can see your pictures in landscape or zoom them in or out with a pinch or a double-tap. The camera also supports photo and video geo tagging.You can tap the iPhone display to focus on anything (or anyone) you want, although the auto focus alone does a very good job. If you want to share your photos or videos, you can trim the video/photo shot just using you finger, then send them via MMS, email, MobileMe or Youtube. iPhone 3GS uses iTunes to sync photos you have on a Mac or in Adobe Photoshop Album on a PC, so that you can have them with you anywhere you go.Cut, copy, and paste
It seems that everything about iPhone 3GS can be done with tapping. For example, you can easily cut and copy words, content from the web, multiple photos or videos and paste them into an email or text message and if you make a mistake, just shake you iPhone to undo.
Voice control
Now you can talk with your iPhone using voice control feature. You can ask it what song is playing and hear it answer. Or call people. Simply say a name or a phone number and your iPhone will confirm what you have requested and dial away.
Compass
iPhone 3GS has a magnetometer working with a Compass application. You can find locations, get directions, see traffic or which way you're facing and even, change your view.
Graphics
The new iPhone 3GS includes 3D graphics support in hardware. With the same 3.5-inch widescreen multi touch display, but now having a fingerprint-resistant oleophobic coating, you'll have faster and more complicated 3D games.
Find your iPhone and Remote wipe
Lost your iPhone? No problem, just log on the Apple's MobileMe service and it will help you find it. You'll have a map that shows the approximate location of your iPhone. Have it play an alert sound to help you find it if it's close to you. If not, you can display a custom message, lock it with a password or initiate a remote wipe and restore it to factory settings.
Nike + iPod
Everybody likes to work out. iPhone includes a built-in Nike + iPod support, so now you can buy a Nike + iPod sensor, slip it in one of your shoes and go do your workout.
Internet tethering
Surf the Internet from anywhere. You don't need a Wi-Fi hotspot anymore as long as you have Internet tethering on your iPhone. You can share the 3G connections with your Mac or PC laptop and connect to the Internet. Moreover, although you have your iPhone tethered, you can still make and receive phone calls. Also you can still connect to the Internet through a USB cable or a wireless network.
Although it has the same design and size, the new iPhone 3GS features are practically insane. In addition to all of the above, iPhone 3GS lets you capture your thoughts, memos, or meetings with the Voice memo feature, see charts and financial details of your stocks with the Stocks application or watch Youtube videos wherever you go. The iPhone 3GS gives you everything you need and more. Phone, iPod and Internet all combined in one.