• 3 Mega Pixel Camera resolution  and the capability to record VGA resolution at the speed of 30 FPS
• 7.2 HSDPA, twice faster than 3G
• More improved battery performance
• Processors are faster
• Double the capacity of RAM
• Double the storage capacity up to 32GB

Not only that, there are more features that makes it a priority to upgrade your phone to iPhone 3GS.

• Faster Web Browsing – Certainly, your inbox and incoming calls are what make up your day. Email application becomes faster and more secure like that of Blackberry. Therefore, no need to carry two phones because your iPhone 3GS is capable of functioning your needed e-mail features. If you have Yahoo! Mail, you can love this push e-mail feature, meaning you can receive email messages faster after they have been sent.
• Great number of applications – there are many applications that have been added that can be downloaded easily on the net. These are blogging interface, application software that allows you to shoot video using your phone’s camera, Skype tools over Wi-Fi and lots of other tools that are beneficial to the user.
• Convenient Games – games can be considered as applications as well. Turning an iPhone into a PSP Play station knockout is really amazing. Games like Spore and Super Monkey had been available in the old models of iPhone but the new model have come up with games like that of a Nintendo DS.
• Free 3G Video – for functionality sake, the second generation iPhone had outsmarted its predecessors in the area of video streaming. The 3G network enable you to watch lot of YouTube video clips even though you are not within the range of Wi-Fi network. Also, the same feature will let you catch your favorite The Daily Show or Lost online. Simply download these shows in its fastest speeds on your computer and have it transferred to your iPhone.
• Battery Life – Apple claims to that the new iPhone 3GS have 300 hours standby time, 24 hours audio playback and five hours of 3G talk time and 3G internets use.