Hi.
you might be able to do it ... there are at least two ways to do it.
1.) get some software to get input from both "nets" ... currently I am not aware of any winxp specific software that can do that (but it might exist), although it might be limited which programs can benefit from it ...
2.) buy a hardware router that can accept two different connections, I know of several brands, but I can currently only come up with one:
http://www.walmart.com/catalog/product.gsp?product_id=2323492&sourceid=27758557422472935024
(This one costs $88 at walmart)
(Actually I could'nt come up with any, so I googled at little to find it : try using "dual wan router" (without aphostrophes, in google) : http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=dual+wan+router
there are many possibilities, but it requires you to be able to get the two WAN connections (NOT ethernet connections, there is quite a subtle difference, as WAN is actually like a phone connector which is a little smaller than the ethernet connector (RJ45), but else the look pretty much alike.
If that is not an option, there might still be some hope, but I do not know an exact solution to this.
Best regards: Jacob Eskildsen / (userid: eskildsen, countryid: Denmark/[DK])