Cisco Network Magic has a notification of any intruders into your LAN. 
They used to have a free fully functioning trial period of about 2 weeks 
(if I remember correctly) when you can determine if you have an intruder.
You may want to look into it to see if it may meet your needs.  See 
http://download.cnet.com/Cisco-Network-Magic/9241-2085_4-11026545-3.html

I hope this helps.

Tom

On 5/15/2013 4:21 PM, Robert wrote:
> I have for a long time had suspicions that somebody is logging in to my home
> Wifi network and using my download allowance. I have used all the
> appropriate settings in the router and use Truecrypt to avoid anybody
> accessing my private information, banking details, passwords etc.  I am
> looking for any software which could tell me if outsiders have found a way
> to use my internet connection. I have a D-link router with 2 wireless PC
> connections and one usb connection.  Any suggestions ??
>
>   
>
> Bob Weaver
>
>
>               

              The NOSPIN Group is now offering Free PC Tech
                         support at our website:
                          http://freepctech.com