>I was trying to find on the web an explanation of the purpose of the virtual directory underneath the web site in IIS 6. Also, I would like to understand the difference between a web site and a virtual directory in IIS 6. If someone knows of a good link, please let me know.

Well, to my understanding, this is the same as IIS 5. A virtual directory allows you to access a directory which is not under the Web site root, as physical directories. This can also be used for other purposes as well.