itunes plugin

My podcasts aren’t loading to my itunes page, although they’re still loading up to my podcast subscription on my phone. The used to be a box that i would put the link to the podcast in when i enter the post in wordpress but it’s disappeared. I downloaded http://wordpress.org/plugins/powerpress/installation/ but can’t install it. What’s weird is that the powerpress folder is there and but it doesn’t show up in my plugin list to activate it.