The TCP/IP Stack is supported through Microchip's standard support channels. If you encounter difficulties, you may submit ticket requests at 
http://support.microchip.com.
The Microchip forums are also an excellent source of information, with a very lively community dedicated specifically to Ethernet and TCP/IP discussions at http://forum.microchip.com.
Microchip also offers embedded network classes through Regional Training Centers. For more information, visit http://www.microchip.com/rtc.