Personal hotspot capabilities for GSM devices — as we exclusively reported earlier today
AirPlay support for third-party native apps and third-party Web apps
Redesigned FaceTime icon
Configurable slide switch for iPad — users can now decide whether the hardware switch above the volume rocker on the iPad controls mute or rotation lock
iAd full screen banners on the iPad — bigger ads… just what iPad users have been clamoring for
Interestingly, iOS 4.3 appears to also have dropped support for Apple second-generation iPhone — the iPhone 3G — and its second-generation iPod touch. This could make the current build Apple’s final software release for these devices.
UPDATE: Several readers have emailed us to point out that enthusiast blog iSpazio may have uncovered a little gem. References to the following effects have been found in the iOS 4.3 code, and they might be introduced as live video effects for video capture and FaceTime calls:
Thermal Camera
X-ray
Kaleidoscope
Normal
Tunnel of Light
Collapse
Turbine
Enlarge
Update 2X:
iOS 4.3 beta 1 for iOS mobile devices and Apple TV seeded to developers.
Multi-Touch gestures to the iPad.
IOS 4.3 will not support the iPhone 3G or iPod touch 2G.
GSM iPhones will get the Personal Hotspot feature with iOS 4.3 (AT&T is a go).
FaceTime gets a new icon and iAds can now display in full-screen.
iOS 4.3 brings the physical screen lock switch back to iPad (is an option).
iOS 4.3 may bring fun video effects to the iPhone/iPod touch camera app.