I'm not sure what your question is.
But if you ask if it is difficult to get ethernet working in uClinux:
No it works pretty much out-of-the-box if you follow the tutorial.
If you ask if it is difficult to write your own program using ethernet under uClinux:
Not easier or harder then it is to write one on a "regular" pc. try googling for it, there are loads of excellent tutorials on this!
Hope this answers your questions...
