NfSen is a graphical web based front end for the nfdump netflow tools.

NfSen allows you to:

    * Display your netflow data: Flows, Packets and Bytes using RRD 
      (Round Robin Database).
    * Easily navigate through the netflow data.
    * Process the netflow data within the specified time span.
    * Create history as well as continuous profiles.
    * Write your own plugins to process netflow data on a regular interval

WWW: http://nfsen.sourceforge.net/