What is Swordfish? You can find some explanation from their site.
Swordfish is a highly structured, modular PIC® BASIC compiler for the PIC18 family of PIC®microcontrollers. Swordfish is a true compiler that generates optimised, stand alone code which can be programmed directly into your microcontroller.
Why did Author select WIZnet W5100 for his project?
The modules allow the use of the modules WIZnet / W5100 in Swordfish. The W5100 has within it all the logic related to the TCP client / server responds to the ping without special drivers, and it is for this reason that lends itself to be used quickly and without a great deal of memory.
Here are example codes.
You can download modules and examples from the following link: WIZ811MJ/W5100
You can refer to this link below for original posting.