I know this tab is correct because I went to Youtube and he taught me how and know I'm spreading the knowledge.  If you want to watch it type in this "Guitar Lesson - Iron Man by Black Sabbath"

     I wrote down everything as he talked and I watched that video many times so I know this is correct trust me, and enjoy.

|--5-8--8---------------------8--8--10-10--
|--7-10-10-5-5-8--7-8--7-8--7-10-10-12-12--
|----------7-7-10-9-10-9-10-9--------------
|------------------------------------------
|------------------------------------------
|------------------------------------------

     Watch the video or listen to the song to learn the tempo but the tab is correct.