Funnily enough I was researching this very topic today….I know the OP asked for a pfs package, but Im also interested in monitoring so I thought Id post this anyway, I came across CactiEZ, but you would have to run it on a spare box, which I plan to do in bridge mode, so it can capture all the data I need, some of the features from the site:-
CactiEZ is a self installing Linux Distribution based off CentOS that sets up and configures a customized Cacti install. Everything is designed to be completely automated and working directly out of the box. This compact distro is loaded with extra features such as Syslog and Netflow data collection, Weathermaps, Reports, Auto Discovery, Router Config backup, Nagios, and much more! Both 32 Bit and 64 Bit installations are possible from the same CD.
This gives your system administrators more time to work on the real issues, and less time configuring and setting up your Monitoring System. Best of all, its absolutely FREE!
Its got quite a few nice plugins, including one for NTOP!
http://cactiez.cactiusers.org/
Ill setup it up in a few days or so when I have the time, Ill report back and tell how well it works with pfs.
EDIT: another application I found http://www.ossim.net/
Slam