Looking at the source code of several podcast feeds, the URL of the attachement seems to be inside the < guid > metatag. I guess that there should be some open specs about this somewhere. A podcast with support of itunes also has many specific meta tags like < itunes:author >, < itunes:keywords >, etc. but I don't use these ...

Could some one tell me how I can build a podcast feed? I can sort-out how to do the rss part, but I do not know how to pass the URL of a media file (eg. mp3, .mp4, etc.) to the feed so that the RSS reader detects this as an attachement to download.