If you have an MSI file that you want to extract contents from, there is no need for third-party software. In Vista, you can extract the contents of an MSI file directly from the command line.

To start this process, you need a command line prompt with elevated privileges (If you don't know how to get one of these, look here: http://www.tipstrs.com/tip/1101/Admin-command-prompt-in-Vista). Once you have your prompt, type the following command:

msiexec /a <file name and path> /qb TARGETDIR=<path to extracted result>

where <file name and path> and <path to extracted result> get replaced with the actual files and result directories you want to use. For example, if I have an MSI file at the location c:\testdir\testfile.msi and I want to put the results in c:\testdir\testfile-results, I'd run the following command:

msiexec /a c:\testdir\testfile.msi /qb TARGETDIR=c:\testdir\testfile-results

Using this command, it is easy to extract the contents of MSI files from the command line without having to download third-party applications.