How can I redirect old posts on my old domain to posts on my new domain?

Let’s say I have blogone.com, and blogtwo.com. I want to import posts from blogone.com to blogtwo.com, and leave blogone.com up for a little while longer. How can I have the posts at blogone.com redirect to their proper imported post at blogtwo.com? (For example, blogone.com/2010/09/11/post would redirect to blogtwo.com/2010/09/11/post automagically, and other posts would follow suit, without me having to manually set up each redirection.)

Any suggestions are appreciated!