If you are getting broadband/cable internet you will need a wireless router and a Wireless card for every computer that you wish to connect to it, if you have a laptop htis may already have one built in. Although if you are getting dial-up internet you will need a bluetooth modem, (i ahve seen a cheap one on www.ebuyer.com before, can't remmber where though) and a USB dongle
There are also telephone extenders that just plug into an outlet then have a receiver. I doubt they'd work as well as bluetooth, but it would be an option and I don't think they are all that expensive...