more arp...

when you ping a device for the first time (as in below) the hardware address becomes associated with the ip address and is placed in the pc's arp table, it does not get associated with the gateway router's interface mac address...

C:\>arp -a

Interface: 192.168.1.9 --- 0x2
  Internet Address      Physical Address      Type
  192.168.1.1           c0-3f-0e-ab-d1-ec     dynamic
  192.168.1.250         98-4b-e1-fb-29-40     dynamic

below is the mac-address-table entry for fa0/17, the port that this device is attached to... the arp table in the pc DOES NOT represent the hardware address of the gateway router...

sw2950_02#sh mac-add int fa0/17
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    984b.e1fb.2940    DYNAMIC     Fa0/17
Total Mac Addresses for this criterion: 1
sw2950_02#

the mac address for this arp is the mac address of the device that was pinged.