I use blog organizer and right now I have about 30 blogs and I'm planning on having at least 100 by the end of the year
what I basically do is log in and manage all the blogs form one place - post, edit posts, add/remove feeds, add links, and so on...
absolutely brilliant and very easy to use !!!!
oh, here's the link btw:
http://bo.cheapestwebsoftware.com/