presley.cobb on "Last modified date"

Im trying to get the last modified date to appear on my pages. The problem is I want to display the last modified date of a different page. So say I have my homepage index.html I want to be able to display in the sidebar a list of pages and next to them the last modified date of those pages. How do I store and retrieve those values so I can display them. Im in the process of learning php so bare with me if im a little slow on the uptake.

THANKS!