The easiest way to find labelled content is to do a quick search for it. If there is a label matching your query, it will be listed above the search results. Clicking on the link will display all content in the site with that label.
You can view all labelled content for a space by going to the 'Label' tab in the 'Browse Space' view of the space.
You can view content labelled with personal labels by going to your 'Profile' and clicking on the 'Label' tab.