Bandwidth tracking/monitoring on Freebsd

[Dragoncrest]

Hi all.  Got a question.  I got a box on my network that I'd like to be
able to track bandwidth usage on.  Just to see how much traffic is
passing through it in a one month period and daily over a 24 hour
period.  Is there some kind of application I can use to log total bytes
sent and total bytes recieved?  I don't need to know specifically WHAT
was sent, but rather HOW MUCH of it was sent.  IE 6 gigs inbound
traffic, 2 gigs outbound traffic.  It's running Freebsd 4.9 right now. 
What is the easiest way to do this short of setting up IPFW and doing a
kernel compile and all that nasty stuff.  Any suggestions will be welcome.