Does Flash Builder 4 now use AIR 2?-Collection of common programming errors

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

How to overlay the Adobe AIR SDK for use with the Flex SDK

  1. Copy the contents an existing Flex SDK folder to a new folder. For example, in Flex Builder, copy the following folder located at: * Windows: c:\Program Files\Adobe\Flex Builder 3\sdks\3.2.0 * Mac OS: /Applications/Adobe Flex Builder 3/sdks/3.2.0
  2. Download the appropriate AIR SDK file for your operating system and save it to the root folder of the Flex SDK. * Windows: AIR20_win_sdk_XXXXXX.zip * Mac OS: AIR20_mac_sdk_XXXXXX.tbz2
  3. Extract the contents of the AIR SDK archive and overwrite the existing SDK files in the copied folder. * Windows: Right-click on the ZIP file and select “Extract All” or use the decompression tool of your choice. * Mac OS: In Terminal, cd to the root folder of the Flex SDK and run this command: * tar jxvf AIR20_mac_sdk_XXXXXX.tbz2

      If you have trouble overwriting files due to file
    

    permissions, try this command sudo tar jxvf AIR20_mac_sdk_XXXXXX.tbz2

  4. In Flex or Flash Builder, open the Properties dialog and choose the Flex Compiler page

  5. Click the Configure Flex SDKs… link
  6. Add the combined Flex and AIR 2 SDK folder created above
  7. Use this SDK for any projects accessing AIR 2 APIs.

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