This is typical for a switched network.  If you are using a Linksys or other recently produced consumer grade "router" then you are most likely on a switched network, therefore will only see broadcast packets and your own.  You could throw a hub in between the switch and modem, and sniff from there.

As far as modes go, some work in Promiscuous Mode, others do not.  You could pick up a cheap PCMCIA card at your local store if you want a card that supports Promiscuous Mode.

If you have any other questions, please feel free to ask.

Hello All:

     Just wanted to wish everyone a Happy New Year, hope everyone had a safe and fun night last night.  This is also the first post of the new year!  So that's a nice thing as well.

     I am new to the forums, I registered just the other day and finally am stopping by to say hello to everyone.  I look forward to joining your seemingly well held together community.

Thanks for having me, have a good one everybody.