BT Tabs is best solution to managing Joomla content (joomla articles, K2 items, modules...) via tabs .It also allows to create unlimited tabs with content of those from back-end, and fully configure with many options.  

If you use BT Tabs, please post a rating and a review at the Joomla! Extensions Directory

Extension features

• Support unlimited tabs
• Support insert Joomla articles, Joomla modules, K2 Items, custom text.. to each tab
• Available 2 layouts for options
• Easy to change tabs position (Top, left, right or bottom)
• jQuery javascript frameworks support
• Compatibility with Joomla 1.6, Joomla 1.7 and Joomla 2.5
• Easy and friendly back-end administration
• Fully compatible: Firefox, IE7+, Opera 9.5, Safari, Netscape, Google Chrome, Camino, Flock 0.7+.
• Video tutorials and forum support provided