Flash IDE versions CS3 and upwards can use ActionScript 3.

Flash Player 9, was the first player to support AS3 SWFs: http://en.wikipedia.org/wiki/Adobe_Flash_Player

What version of flash uses Actionscript 3?
I'm developing a web application using ASP.NET MVC (I'm new to the framework and actually quite new to web development in general). My application must support multiple languages - there's a bunch of countries for which I need the application to "speak" the local language. 

The UI concept is common - have flag icons somewhere, usually the top, possibly with an additional drop-down to include less common languages. At this stage I don't want to get into automatically detecting the source country, but rather start with English and allow users to choose otherwise (and I would remember that setting of course). 

I would like to know if there's any "framework" for supporting such multilingual views in ASP.NET MVC that will make the job easier.

Any recommendations?

Thanks
