Is there any libraries that can connect two or more computers that are on a lan together and send data to eachother?

Here's the best tutorial on the net

No.
Tutorial are not professional at all (by kids...)
Read Network Programming books (easy to find in ebook format)

commented: No. -5

Tutorial are not professional at all (by kids...)
Read Network Programming books (easy to find in ebook format)

A tutorial is a great way to learn the basics of subject in a relative small amount of time. When you understand the basics, you can always buy a good book to get you deeper in the theory.

I know you're probably not going to respond, but I'm just curious: Why do you keep posting these utterly useless replies? You're not helping anyone with comments like:
-- Read an ebook!
-- Use win32!
-- It's on MSDN

Don't you ever get tired of it?