Today, I came across two nice articels from IBM DeveloperWorks. I think they are really good for beginners. So, I putting here for everyone.

1. Programming Linux sockets, Part 1: Using TCP/IP

2. Programming Linux sockets, Part 2: Using UDP

Both the articles are written by, David Mertz, Ph.D. (mertz@gnosis.cx) and the skill level is Introductory for both.