im ordering the sar110 adsl modem/router, but just wondering where in the pc does it actually connect to if I want to have my pc and xbox on the router, is this definatley possible with this, and how will it be done?
The best (or easiest, as well as most flexible) option would be to purchase a 10/100BaseT ethernet hub or switch. Connect the ethernet port of the ADSL router to one of the ports on the hub/switch, and connect the PC and Xbox to 2 of the other ports. With networking properly setup, all three devices should have no problem accessing the Internet.
You can also use your PC to provide connectivity to the Xbox, provided there are two network cards/ports present in the PC, via a crossover cable, but that approach is somewhat more involved.