I don’t know if this is what your looking for but this is the easiest way:
On your dashboard you probably have a widget that shows a feed like “WordPress Dev Blog” or “Other wordpress news” or something like that.
Just hover over the title of the feed and a configure option should occur.
Click that and direct it to any feed you want.
To add more feeds use this plugin: dashboard-latest-news
It says compatible up to 2.8, but works in 2.9.1 for me.
– Espen.
You should have a look at the ‘front page excluded categories’ plugin. It may give you som hints on how to apply it to other places as well.
And i googled a bit:
Just in case i found something you didn’t. Though i suppose you have googled a bit yourself too.
(Excuse my English, I’m Norwegian)
– Espen