FeedForAll Mac 

Create, edit, publish rss feeds, podcasts for iTunes. New RSS feeds and podcasts can be quickly edited or created with FeedForAll Mac. Advanced support includes name space extensions allowing users to make iTunes, Yahoo and Microsoft compatible feeds
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FeedForAll 

Easily create, edit and publish rss feeds and podcasts. New RSS feeds and podcasts can be quickly and easily created with FeedForAll. Advanced features enable you to create professional looking rss feeds and podcasts quickly and easily.
rss rss feeds feed feeds create edit publish xml xml feeds news feed newsfeeds podcasts podcast podcasting

NewzAlert Composer 

NewzAlert Composer is a comprehensive rss editor for creating and publishing RSS feeds. It is all you need to get up and running with one or more RSS feeds of your own, and will have you up and running within minutes.
rss editor publisher news xml feed