This model is the successor of the second generation of iPhone 3G, and the predecessor of the fourth generation, the iPhone 4. The device was launched on June 19, 2009 in the United States and Canada, and on June 26 in Australia and Japan, while the rest of the world had to wait until July and August, 2009.
The iPhone 3GS was first introduced in 2009, at the Moscone Center in San Francisco, at an event called WWDC 2009 (WWDC is held every year at the Moscone Center in San Francisco, and it is where all iPhone models were first introduced). The primary features of the device consist in hardware improvements, regarding its speed. Improvements also include Voice Control, a higher resolution camera, support for video recording and HSDPA 7.2 Mbit/s downloading (due to Apple not implementing the HSUPA protocol, the upload speed remains 384 kbps).
The iPhone 3GS uses Apple's Mac OS ased operating system called iOS ( first called iPhone OS), which is used on all iPhone models.
The phone can run a large number of applications, as long as there are aproved by Apple itself, and obtained through their AppStore online store. Running unchecked third party applications and obtaining them throug unauthorized sources may lead to sever software complications which will no be covered by the phone's warranty. Like all other iPhone models, the 3GS's control mechanism is built around the capacitive touch screen. The 3.5 inch liquid crystal display was designed by Apple, but manufactured by LG, and it was intended for the usage of bare fingers.
However, people still get a surprise when they find out that normal gloves and styluses do not work on the screen, because they are not able to generate the needed amount of electrical conductivity for the screen to respond to the finger's gesture. If you really want to use a stylus, you can get a special designed stylus for this purpose.
The 3 megapixel camera is the first in the history of iPhones to support video recording. It also presents some nice features like the tap-to-focus feature, which allows users to focus on a desired spot by simply tapping the screen in that spot. Another feature is the slider which appears when taking a photo, which allows you to switch between the photo camera and the video recorder.