WordPress MU

Has anyone tried changing the domain of your MU installation before?

What are the steps involved?

Any easier ways other than importing the database into the new domain? How about blog.dirs permissions?

I did that with old WPMU (1.3.3)

I exported the DB into sql file and did search-replace. AFAIK, nothing to do with blog.dir permissions.

Might be a good idea to try doing this by simply going to Edit menu of the main blog, but I never tried this way.

Do I need to download all the blog.dir folders and upload at the new domain?

I think yes. Or you can use symlinks if both domains are on the same server, or just move dirs on the server. But if 2 domains are on different servers - yes, you have to copy files unless you want to generate traffic :)