It’s not the iPhone 5, but like it or leave it – and investors apparently want to leave it – the iPhone 4S is Apple’s next evolution of its iconic smartphone. The company today unveiled the 4S at an event held at Apple headquarters in Cupertino, Calif., with new CEO Tim Cook presiding over the presentation.

The iPhone 4S will sell for $199 and will be available through AT&T, Sprint and Verizon Wireless beginning Oct. 14, with preorders opening on Oct. 7.

Apple says the iPhone 4S can intelligently switch between two antennas to send and receive and features HSDPA connectivity for up to 14.4 Mbps download speeds. It’s also a “world phone,” so both CDMA and GSM customers can now roam internationally on GSM networks.

While Apple addressed a number of its business segments, from mobile software to new iPods and a significant carrier addition here in the United States, none of today’s news seemed to satiate investors. The company’s stock dropped 18 points, or just under 5 percent, to $356 per share immediately following the announcement.

With all the anticipation inherent in an Apple event, today’s attendees were left to an especially long wait before the company started unveiling new hardware, which aside from the 4S, also included a refresh of the company’s iPod line of portable music players. Prior to the juiciest bits of today’s presentation, Apple execs took a long time, over 40 minutes, rehashing features of the previously announced iOS 5 and iCloud products. Both will be officially launch on Oct. 12.

Undoubtedly, the star of today’s show was the iPhone 4S. While the new iPhone maintains an identical form factor to the old iPhone 4, it does include beefed-up insides. The iPhone 4S features a dual-core A5 processor, 8-megapixel camera with 1080p video capture and an IR filter for more accurate colors. The phone also maintains the existing old iPhone 4’s pricing structure. Both black and white versions come in at $199 (16GB), $299 (32GB) and $399 (64GB). The iPhone 4 is now $99 for 8GB, and the 8GB 3GS will be free with a two-year contract.

What’s interesting about today’s announcement is that the new hardware actually played second fiddle to a new software feature and the announcement of Sprint as an additional carrier partner in the United States.

On the software side, the iPhone 4S has bake- in integration of the virtual assistant Siri, which the company acquired when it bought the company back in April of 2010 for an undisclosed amount. Siri allows users to simply speak to their phone to schedule appointments, dictate emails and texts and search for information on the mobile web. The trick here is that users can say just about anything they want, instead of the usual speech recognition game where actions are dependent on specific commands.

A live demonstration of the Siri technology seemed to catch the attention of live bloggers posting to both The Wall Street Journal and Engadget websites. “This is, seriously, some impressive stuff happening here,” wrote Engadget’s Tim Steven at one point during the demonstration.

But perhaps the most disruptive thing Apple did today was bring Sprint on board as a carrier partner, confirming a report published yesterday by The Wall Street Journal that claimed Sprint had committed to buying at least 30.5 million iPhones, even though it would likely lose money on the deal until 2014. That report cited people familiar with the matter.

Apple also unveiled a refresh to the iPod Nano and iPod touch. The new iPod Nanos will get volume buttons, FM radio, pedometer and integrated clip. The new models will sell for $129 (8GB) and $149 (16GB).  The iPod Touch is now thinner and features a retina display, FaceTime support, HD video recording and a gyroscope.  Those units will sell in black and a new white version for $199 (8GB), $299 (32GB) and $399 (64GB).