It's official. During his MacWorld keynote, Steve Jobs introduced the iPhone to the world. So how are people reacting?

• A New Smartphone OS Rival? Symbian Guru Steve Litchfield gives his thoughts on the new kid on the block.
• At Long Last, Apple Unveils the iPhone. Ed Hardy gives a short spec summary.
• Apple iPhone to Revolutionize the World. Michael Kwan features some previous iPhone concepts, a size comparison, and a some photos of the device itself on display.
• Steve Jobs Introduces Apple iPhone. A more detailed discussion of the specs by James Alan Miller.
• Financial Impact of iPhone Announcement. Apple's fortunes are already increasing even before the iPhone's release.
• Introducing iPhone. Of course, there's nothing wrong with checking out Apple's own product site.

What else do you need to know? The apple iphone has a 3.5" 320 x 480 touch-sensitive screen. Aside from playing music and video, it's a Quad-band GSM (850/900/1800/1900) smartphone that runs OS X, and comes in 4GB and 8GB flavors. The connectivity package is good, with built-in Wi-Fi (802.11b/g) and Bluetooth 2.0. A 2.0 megapixel camera rounds out the deep feature set.

Cingular subscribers (4GB for $499, 8GB for $599, both with two-year contracts) will get first dibs this June, Europe follows near the end of this year, while Asia comes in last at 2008. Expect The Smart PDA to cover related developments as they happen.