You ca buy a second Wireless Router and configure a segregated Network.
Here is the principle, http://www.ezlan.net/shield.html
Jack (MVP-Networking).

"Netorius77" <Netorius77@discussions.microsoft.com> wrote in message
>I am a relative novice in the area of networking and would appreciate some
> help.
> I have a XP Home desktop connected via ethernet to the internet via ADSL2+
> modem/Router (D-link DSL-G606T). I have added my kids PC and a printer to
> the
> network via the ethernet ports and my Laptop (Vista Home Premium) connects
> wirelessly - all works great. I use WPA for the wireless security as I do
> use
> file sharing to enable central storage of personal files on the main PC.
> My question: Is it somehow possible to enable guests at our home to
> connect
> wirelessly to our internet connection without providing them access to my
> shared files, but still retain the file sharing I have?
> Thanks