The lastest PrestaShop™ 1.4.6.2 added new features to customize top and bottom menus.

Back Office > Modules > in search box type top for [Top Horizontal Menu] and cms for [CMS Block]

Top Horizontal Menu v1.3 (add a new menu on top of your shop)

• customize menus / submenus from CMS / Suppliers / Manufacturers / Categories / Products / Menu Top Links
• add/remove custom Link via Menu Top Links
• enable / disable search bar

CMS Block v1.1 (adds a block with several CMS links.)

• allows CMS block configuration
• enable/disable [Display "Powered by Prestashop"]
• enable/disable [Display the Footer's various links]
• allows footer’s various links Configuration