Network programming

I wish to learn more about how to write programs that interact with other computers over the internet. Do you know of any good book and/or website I could read on the subject?

As always /prauge/ is not about programming.

This is an excellent book/tutorial: http://beej.us/guide/bgnet/
All on one page, for your wget pleasure: http://beej.us/guide/bgnet/output/html/singlepage/bgnet.html