Associate links with specific categories?

I am not sure I understand what you want. You should give more details, more importantly, describe what you want – not the technical things but the desired end result.
Where do you want this? Backend? frontend? Why?

Users aren’t always so good at selecting the right categories. So I was thinking that if you had a link that automatically populated the check box of a certain category, it would be a foolproof way of getting the user to select the right category.

For example, if you’re using wordpress as a writing class blog, and you want all your students to select a category called “assignment #4,” wouldn’t it be great if you could code a link such that by clicking it, “assignment #4” was automatically selected?

If this isn’t possible, just let me know.

I wish it WERE possible, but aside from the fact that anything not specifically categorized being assigned to the “default” cat, it appears no one but the two of us would like something like this.

The only thing wp does is use an auto-populated checkbox for default. The only way to set up something like you’ve postulated is change it on an “assignment basis” – in other words, change the default cat as each assignment period changes.

Thanks.