What's the latest version of Flash?
The latest versions of Flash are:
There are different versions of Adobe Flash for different platforms. The standard version is the one available on most computers (eg. Windows & OS X). Other platforms have different versions.
Flash Standard: 22.214.171.124
Flash on Linux: 11.2.202
Adobe have announced that they have ceased developing Flash for Linux. If you're running Flash natively on your Linux machine, please consider uninstalling it and using Google's version of Flash (named "Pepper") in Google Chrome.
Flash on Android: 11.1
Adobe have announced that they have ceased developing Flash for Android. If you run Flash on your Android device, please be aware that it's considered very out of date and probably has security problems. You should consider uninstalling it and finding alternatives.
Find out more about Flash
Check out Adobe's page on Flash to learn more about it.
The future of Flash
Steve Jobs wrote an excellent explanation of the state of Flash and why it Apple will never let Flash run on their mobile devices. It seems self evident now, but in 2010 this opinion ruffled a few feathers. [Link]
It's not all over yet though; FastCompany.com wrote an article about this: The Agonizingly Slow Decline Of Adobe Flash Player.