I write a blog at some site. When I write a new post to that site, is there a way to automatically post it to my WordPress and Blogger blogs as well?
You can autopost to blogger, WP and other services, if you have a blog at Posterous. Posterous lets you autopost to several other services automatically. If you have a self hosted blog at WP, you can try out a few WP plugins which would let you do the same thing.
To Publish the Same Blog Post to Multiple Blogging Sites at Once, See following Article: