The Refeed plugin for Movable Type 4.0 (MT4) provides an easy way to pull in content stored in multiple external blogs and republish or "reblog" that content locally in Movable Type.
It works by providing administrators with an interface into which they can enter as many URLs to RSS and Atom feeds as they wish. Movable Type will then monitor those URLs for new content and pull in that content into a blog. All data will be preserved from the source feed, including all relevant dates.
A permalink to the source content is stored within each reblogged entry's Keywords field.