Installing and deploying on a (mt) Media Temple Grid-Server is pretty straightforward. They have set up a Knowledge Base article that goes over the details: http://kb.mediatemple.net/article.php?id=152

The differences are basically:

• mysql/pgsql database servers aren't local, so in database.yml instead of using 'socket: /tmp/mysql.sock' you must use something like 'host: internal-db.s####.gridserver.com'
• (mt) uses mongrel and the 'mtr' command to connect the RoR container to the Grid. Instead of using 'script/server' to start your app you must use these four commands to hook your app to a domain, generate the proper htaccess file and start it
  • mtr add radiant $PWD radiant.customerdomain.com
  • mtr generate_htaccess radiant
  • mtr create_link radiant
  • mtr start radiant
• The mtr command automatically puts your app in production mode so you do not have to edit config/environment.rb or set it any other way.