If you get a modem/router, you can dispense with the need for a separate modem. There are dozens to choose from; I've had a Netgear 834G and Thompson Speedtouch. Both were very straigtforward to set up and reliable in use. Your PC is unlikely to a have a wireless card fitted (but check) - if it doesn't they are cheap as chips, as are plug-in dongles. Your new netbook will be wireless enabled.