Limit number of posts on just the home page.

[Eric Schmidt]

Hello,

I am creating a blog that will feature posts from 40 departments each 
month.  I would like to have only one introductory post appear on the 
main home page with links to the different categories where the rest of 
the posts will appear.  Is there a way to limit the number of posts to 1 
for the main page but allow for multiple posts to appear when a specific 
category or tag is viewed?

Thanks,
Eric Schmidt