You can monitor your system's Web performance quite easily with graphical Linux tools. You'll learn how to use several in this chapter, including MRTG, which is based on SNMP and monitors raw network traffic, and Webalizer, which tracks Web site hits. How-To: http://www.linuxhomenetworking.com/linux-hn/mrtg.htm#_Toc92809392
I did not have the time to test this yet, but I found another good link to a mini how to mrtg for debian: mini-how-to maybe someone can use it / test it ;-)
You are talking about this? : http://www.web-hosting.co.yu/mrtg/ BTW There's lot posts on the faorums about having difficult time to make it work (me too) but after this tutorial it works prefectly! http://www.debian-administration.org/articles/366
yes, it is both munin (and monit) and falko's tutorial are great. I am using munin (and monit) too phpsysinfo and mrtg also