Activating the SharePoint Server Publishing Infrastructure feature adds the Administrative links on the Site Settings page, including the ability to manage Master Pages for both publishing and non-publishing Web sites, Navigation, Searchable columns, Content and Structure, Content and Structure Logs, Variations and Translatable columns.
The publishing feature also includes a publishing approval workflow to help ensure that the information shared is reviewed for quality and correctness.
To enable publishing on a team site go to Site Actions > Site Settings > Site Actions > Manage site features and select Activate SharePoint Server Publishing.
When you look at the feature folder ..\14\TEMPLATE\FEATURES\PublishingSite you can see what is additional functionality is added to your site
For a good overview you can also look at the following post SharePoint Publishing Features Functionality