Customize the 2007 Office system
http://technet2.microsoft.com/Office/en-us/library/9df1c7d2-30a9-47bb-a3b2-5166b394fbf51033.mspx?mfr=true
What do you have to know before and be to attention?
Customize Setup before installing the 2007 Office system
Configure feature installation states of the 2007 Office system
Configure user settings for the 2007 Office system
For complete information about the OCT, see Office Customization Tool in the 2007 Office system
What you can do with the Config.xml file?
Config.xml file in the 2007 Office system
For more information See what´s new in the Setup for Office 2007