plus a PCMCIA or USB wireless network adapter for the laptop, and a USB wireless network adapter for the PC.
Plug the router (get one with its own inbuilt ADSL modem) into the ADSL telephone line, and set it up as per the instructions - it will be a very straightforward procedure. Now install the network adapters on both laptop and PC (handy tip: install the software BEFORE you connect the adapter in both cases).
Reboot both machines, and you'll be sharing the ADSL connection on both. The advantage of using a router is that you can use either of the computers without the other one being switched on - it's the router which makes the connection to your ISP, and it will stay online as long as it's switched on. Don't forget to turn it off when you go to bed, or go on holiday, there's no point in sitting online when you don't need to be. The router will automatically connect as soon as it's booted.