There are several definitions for the Knowledge Worker. The use of the term ranges from everyone is a Knowledge Worker in one category or another to a Knowledge Worker is someone with an explicit job in creating knowledge—Scientists, Engineers, Programmers, etc. See the links below to learn about the Knowledge Worker.

Wikipedia is always start for a definition of a term.
Knowledge worker

This is a straight forward definition.
What is knowledge worker?

Here is a little more in depth concept of the Knowledge Worker.
Specialist Library Knowledge Worker

This article is a well done essay that discussed the Knowledge Worker.
Technological Unemployment in the Information Economy

This site will help you to become a Knowledge Worker.
A reading list for aspiring Knowledge Workers

This is quite short, but is a discussion about managing the Knowledge Worker.
Column Two: Managing the knowledge worker

This is a quick read and I like this author’s take on the Knowledge Worker.
Knowledge management: No such thing as knowledge worker

You might need to get past this writer’s personality, but in the end he has some good points.
Happiness for knowledge workers

This is short, but there is an interesting statistic mentioned here.
judith meskill’s knowledge notes…: The Knowledge Worker…

Here is a short, well done article that covers managing the Knowledge Worker.
ScienceCareers.org | Managing Knowledge Workers