I am sorry to say that there is no App Note that tells you how to hook up PSoC1 to an ethernet. I am not aware of any, if I find anything will post it here.
you can go to 8052.com, there is an old project of TCP/IP stack for 8051. There are some other application for devloping IP stacks for PIC or Atmel CPUs(I think but not sure). However, PSoC1 is a not a good candidate for such application, but it is doable.