Since you want to pipe the text output through your program, the following fragement might help:

#!/usr/bin/perl
use strict;

while (<>) {
    if ( /IP\s+(\d+\.\d+\.\d+\.\d+)(\.(\d+))?\s+>\s+(\d+\.\d+\.\d+\.\d
++)(\.(\d+))?\:\s+(\w+)/ ) {
         my ($srcip, $srcport, $dstip, $dstport, $proto) = 
            ($1,     $3,       $4,     $6,       $7);
         # icmp: port := 0 (should be n/a)
         printf "%16s [%5d] --> %16s [%5d] (%s)\n",
                 $srcip, $srcport, $dstip, $dstport, lc($proto);

    }
}
__END__

Piping your example through it yields (works with: tcpdump -nlq):
  192.168.11.128 [ 3415] -->      66.249.93.9 [   53] (udp)
    66.102.9.104 [   80] -->   192.168.11.100 [40323] (tcp)
  192.168.11.100 [40323] -->     66.102.9.104 [   80] (tcp)
    192.168.11.6 [   22] -->   192.168.11.128 [59921] (tcp)
  192.168.11.128 [59921] -->     192.168.11.6 [   22] (tcp)
   72.21.192.209 [   53] -->   192.168.11.128 [49172] (udp)
  192.168.11.128 [    0] -->    72.21.192.209 [    0] (icmp)
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