It has been released. If you want to download it you can download it from here.
http://www.ihacki.com/index.php/downloads/viewcategory/10-apple-iphone-ipad-firmware-ipsw-filesOn September 19, 2012
Probably not. The only OS for iPhone currently in beta is iOS 6. There are is no iOS 5.1.2 currently in beta and iOS 6 should be out within a few weeks. Unless a security hole in the current iPhone OS is found before 6 is released, don't expect an update to iOS 5.
iOS 6 is free.
Yes, when iOS 6 comes out it will be free of charge, just like iOS 5 and iOS 4 were.
It is due out for this fall. Probably around the same date for iOS 5 and 4S. No specific date has yet been released, but see related links for a preview of what to expect.
iOS 4.3 is a level iOS, Apple's mobile operating system, hence the name. Apple's iPhone, iPad and iPod Touch run iOS software. The latest level of iOS is iOS 5.1.1. However, it is expected that iOS 6 will be released at the WWDC this month. If you have any further questions regarding Apple and iOS, please contact me. Henryhen.
Some ios 6 devices can be jailbroken.
It was released on the 12 September, 2012
Yes you can.
No. It is just to soon for the devs to get an untethered jailbreak for iOS 6. Plus iOS 6 isn't available to the public just yet.
Yes. All iPad minis should be running iOS 6 and can update to iOS 7 this fall.
The new iPad (3rd Generation) will get Siri when IOS 6 is released this fall.