Just a warning if you are uploading podcasts: if your filename has spaces in it, the rss feed/enclosure tags will not work properly. In fact, you will notice the mp3 file doesn't show up at all in a feed.
Took me a while to figure this out. Replace the spaces in your filename ON YOUR SERVER with dashes or underscores.
WordPress media upload does this automatically. Add from Server does not.
Took me 2 hours to figure this tricky problem out!