Wordpress Blog Post Extractor

We would like to develop a server end software script, that would "copy" contents from a selected wordpress blog (or several). In other words, A spider that would replicate posts from one wordpress blog to another. The spider needs to: 1. "Look" at the selected Wordpress blog. 2. Extract each post (Images and text) 3. Replicate the Exact post(s) onto an existing provided WordPress blog, Including all fields (Title, Text, Images). (E.G automatically log in as admin and replicate posts) 4. Have the ability to spider through hundreds or thousands of blog posts and replicate them on another wordpress blog. Or the ability to feed the program direct links, and it will then spider that link for all blog posts. 5. 6. If easier, the spider may be fed a "list" of specific pages, so that it doesn't have to "search" the blog. I.e A defined list of permalinks through a text file.