Theres two options I would recommend!
I use both of them and its all about time.
http://wordpress.org/extend/plugins/wp-o-matic/ - This is if u want to run it directly in wordpress.
In my situation I use a lot of rss feed blogs to just gain very small amounts of traffic and feed it through to my main site!
So for that reason I use Blog Organizer from -
http://bo.cheapestwebsoftware.com/
Basically that holds like all my various feeds and I just select which sites want to use the feeds.
I prefer using wordpress for the blogs themselves but you can do that and then get Blog Organizer to operate anything feed related. They also have Blogs Automater which may well just be what you need! Also works lovely with wordpress.