SharePoint 2010 - Navigation
  
  How to add custom links to current navigation
 
    SharePoint 2010 allows you to customize your current navigation by adding   custom links that are not in the typical site hierarchy. Use this feature with   caution, because custom links have to be manually updated if a change is made to   the URL of the custom link.
    Add a Single Link to Current Navigation
    To add a single link to your current navigation:
    
      - Click Site Actions, and then click Manage Content   and Structure
- Scroll over your site name in the left window pane and from the drop-down   menu choose Site Settings
  
- In the Site Settings window select Navigation under the Look and Feel Section 
  
- In the Navigation Setting window scroll down to the Navigation Editing and Sorting section to view your Global and Current Navigation 
  
- Select the Current Navigation folder and select the Add Link button. 
  
- Complete the fields in the Add Link window. The title will   appear in the navigation. The URL will be the link to an external site or you   can link to another page within your site. If linking to an external site (which   we don’t recommend in the current navigation) be sure to select the check box   for Open Link in New Window. The description will appear when   the mouse hovers over the link. It is recommended you leave the audience field   blank so all site users can see the link. Select OK when done. 
  
- You should now see the new link in the list under Current   Navigation. You can sort the link by using the Move Up or Move Down buttons to position it in the order you   desire.
  
Note: If you need to delete this custom link, select the   link name and select the Delete button. 
    
      - Select OK when done adding your single link to your current   navigation.