Site Map vs. Site Index (newbie type question)

[cruby]

I am struggling with our main library web page on our company intranet.
Every time I think we finally have the page designed so that people can find
stuff we either add a new service or my manager decides something is buried
too deeply and wants me to bring it to the top level.  If I put everything
on the first page, the page is going to get really crowded (it's all ready
looking too busy and we just updated the format two months ago!).  I'm
wondering if I need to go to a site map or site index for our page.  Being a
relative novice at this, the really fancy stuff we have like JavaScript I
have had another department do, I am not sure what the difference is between
a site map versus a site index.  Can someone either give me a good
explanation or a source to check for an explanation or point me to some
examples of the two?

Any help you can give would be greatly appreciated!

Carolyn

Carolyn Ruby-Weilage
Library
Micron Technology
Boise, ID 83707
cruby at micron.com (e-mail)