I'll repeat my recommendation for OpenNMS. Getting started is as easy as 'yum install' (almost...). And it can do about anything you'd want in a monitoring system - including matching up those switch ports with the connected devices.
Les, at first I didn't heed your advice because I figured it would be another ten hour battle to get opennms installed. I was pleasantly surprised to find that that it installed in ten minutes using yum on my CentOS 5 box. Much slicker interface than netdisco, and it discovered all the ports on my switches on the first try. Thanks for the suggestion!