How do you extract data off of an iso file?

You will need to mount the file to a cd/dvd of Flashdrive. You will need a program capable of mounting these images. I recommend CDBurner XP. It is free, and available through cnet's download.com. After mounting the iso to your chosen media, install the software as normal. This is used when the iso file is an installation for an application.

ISO's are also used as a bit torrent file format. These are usually archives of files, such as Music, movies, books, etc. These only require that you use a bit torrent software such as Frostwire or Utorrent. These programs are also free, and can usually be found on download.com.