Please see this post on our blog
http://kolyimmd.blogspot.com/2008/08/how-to-create-custom-team-and-use-it.html on how to import a custom team that you have created into your saved game file.
Remember you can create a saved game, import teams and use this as your starting team file for a game. Just make sure you save the game as soon as you open it to something else so you do not overwrite the initial saved game file with all the custom teams.
You will have to use the
Kolyimmd Football Manager 2008 - Saved Game File Editor to start the game as a manager of a different team.
