The Windows AIK download file is in a .img format. Many burning programs like MagicISO, WinISO, etc. can handle the .img format. If you don't have a program that will handle it, you can download a free program called ImgBurn. ImgBurn will burn the .img file directly to a DVD. These instructions will guide you through the process.
If you haven't already, you'll need to download the ImgBurn program.
Go to the ImgBurn website and click on the Download link.
Select a download mirror (I selected 'BetaNews' in this example) and click on it.
Click the Download Now link. (If you select a different download mirror, the download page and link will be different than the image below.)
If you get a security warning, right-click on the yellow bar and select Download File... from the pop-up menu.
Click the Save button to save the download to your computer.
Browse to the folder to which you want to save the download and click the Save button.
Wait for the file to download. It shouldn't take very long as it's a small file.
When the download is complete, you can click the Run button to immediately start the installation or you can click Close and run the file from its saved location on the computer (this can be opened by clicking the Open Folder button).
When you run the downloaded ImgBurn installation file in Vista and have UAC turned on (the default), you'll need to select the option to allow the program to run.
Click the Next button to begin the installation.
Check the options you want and then click the Next button.
Select the installation folder (it's recommended to leave it at its default value) and then click the Install button.
During the installation, you may be asked if you want ImgBurn to check for newer versions. Select the choice that you want.
When the installation is complete, you should see the following screen. If you leave the Run ImgBurn checkbox checked, the program will start automatically when you click the Finish button. Otherwise, you'll need to start it from the Desktop icon or from the Start Menu.
When you start ImgBurn, you'll see the main selection screen. Click on the Write image file to disc option.
Click the Select File button or select Browse for a source file... from the File menu.
Browse to the WAIK .IMG file you downloaded, click on it to select it and then click on the Open button.
Insert a blank DVD into your DVD writer. The DVD drive and disk information should show up in the right-hand side of the ImgBurn window. Click on the Write to DVD option to burn the WAIK .IMG file to the DVD.
Wait for the DVD to finish burning. If you left the Verify option checked (the default), ImgBurn will eject and reinsert the DVD after it finishes burning it and verify that it was written correctly.
When the burning is complete, click the OK button.
You can now exit ImgBurn and use the WAIK DVD to install the Windows AIK.