I just got CS5 master suite which includes Flash Builder 4 and Flash CS5 Pro.
When I create a new AIR app in CS5 pro it says "AIR 2" but when I create a new AIR project in Flash Builder I do not see anything indicating that it is AIR 2 or 1.5?
Is there a way to tell which AIR runtime it is using?
I think you'll have to download the SDK and st it up yourself; but Flash Builder should work fine:
http://labs.adobe.com/wiki/index.php/AIR_2:Release_Notes
To update this for the production release; go downlod your preferred version of the Flex SDK at http://opensource.adobe.com/wiki/display/flexsdk/Downloads and download the AIR 2 SDK at http://www.adobe.com/cfusion/entitlement/index.cfm?e=airsdk .
Overlay the two using the instructions above (1-3); then configure the new SDK in Flash Builder (also using the instructions above (4-7).
Update: Since my original post of this; Flex 4.1 SDK was released which includes the relevant AIR 2 bits. You can get it here
The fastest way to use AIR 2 is to download a new version of the Flex framework. I've downloaded version 4.1.0.16076 from here and it comes with AIR 2 already installed.
Today Adobe release the stable version of AIR 2 SDK so probably they come up with a new stable release of the Flex SDK.