Although Apple has sent out Let's talk iPhone invitations to the press and it is highly likely that it will announce the release information of iPhone 5 at the Oct. 4 event, people can hardly wait to catch a glimpse of the next generation iPhone.

Apple’s iPhone 4 is the best selling smartphone in the market currently and iPhone 5 is supposed to bring significant advancements in terms of hardware and software changes. How advanced will it be? Rumors claim that it will be bigger and faster. How big? How fast? Will the iPhone feature a better camera? More RAM? The questions can be endless.

iPhone 5 is also expected to feature a SIM-less design with 3-4 internal antennas for both GSM and CDMA networks. Probably it means that the new iPhone will be a world phone. There is also talk that Apple could be including a special SIM card slot in iPhone 5 for users to insert a SIM card when traveling outside the US.

Apple's recent patent filing lends support to the expectation that iPhone 5 will be a world phone. In one patent configuration, Apple has decoupled the subscriber identifier values from the operational parameters specific to a wireless service provider. That implies that the user can use the same device at places with different carriers. For example, the user can subscribe to a primary carrier at home and to a secondary service provider while traveling abroad.

The physical home button is also expected to be replaced by a touch-sensitive ovaloid area which takes up the middle half of the bottom border.

9to5Mac, Cult of Mac, CNet UK and MacRumors echo the same sentiment.

Photos posted by MICGadget, which purportedly are of a production center of iPhone touchscreen in China, also suggest that iPhone 5 will come with a touch-sensitive ovaloid area that will replace the home button.

Other new features expected to appear on iPhone 5 are:

> 4G LTE compatibility
> Improved voice recognition features
> Wireless charging capability
> Improved battery life
> More powerful gaming capabilities supported by multi-core A5 processor and Imagination Technologies' PowerVR Series6 mobile graphics processing architecture

Most importantly, iPhone 5 is expected to come pre-installed with the new iOS 5 mobile operating system.

iOS 5, which was unveiled during Apple Worldwide Developers Conference (WWDC) in June, boasts of true multitask capabilities and comes with loads of new features such as News Stand, Reminders, Delta Updates and iMessage, Apple's very own messenger service.

Meanwhile, rumors are also making rounds on the Web that Apple will also release a budget-friendly iPhone, dubbed iPhone 4S, which will be have less features than iPhone 5 but will lower the entry barrier for iPhone users.

Earlier, Vietnamese website Tinhte.vn had uploaded photos of a device that it claims is of iPhone 4S, the rumored lower-cost model of the iPhone 4 that reportedly will be launched together with iPhone 5 in September. Tinhte is the same blog that that got ahold of the iPhone 4 ahead of its official launch.