Hi Friend,
The Cisco 2800 Series routers are the follow-on platforms to the Cisco 2600 Series. The Cisco 2800 Series offers up to a five-fold chassis performance improvement, twice the default memory, and dramatically increased slot performance and services density, while maintaining support for most of the more than 90 existing Cisco 1700 Series and Cisco 2600 Series interface cards and network modules (on Cisco 2811, 2821, and 2851 only).
Also Cisco 1700, 2600, and 3700 series modular access routers' end-of-sale (EOS) date is March 27, 2007.
HTH
Ankur