Sorry, I forgot there were more, weird steps.
1) Go in to Network Admin -> Sites and edit the site you want to BE the new 'main' domain so it's url is http://example.com (remove the subdomain or subfolder path totally). There's a checkbox to change site and home URL. Make sure that's checked before you hit save.
2) Change the
define('BLOG_ID_CURRENT_SITE', 1); to whatever you want. Save it, upload it. DO NOT CHANGE SITE ID, YOU WILL BREAK THINGS.
3) Go BACK to Network Admin -> Sites and edit the site of the 'OLD' main site. Edit it so it HAS a subfolder pathing. /edition2011/ or whatever you want. Make sure the checkbox is checked. Save it.