The easiest way is to buy WLAN adapters for both your laptop and your PC, creating a peer-to-peer wireless connection between them. Enable Internet connection sharing and voila! your laptop will have access to the Internet. The steps involved:
1) Plug a USB wireless adapter (~$50) into your PC.
2) Insert a PCMCIA wireless card (~$50) into your laptop.
3) Configure both wireless adapters for peer-to-peer (ad hoc) connections. Both must use the same SSID, channel, and (if you enable WEP) encryption keys. Give each connection a static IP address: for example, assign 192.168.0.1 to the PC and assign 192.168.0.2 to the laptop. Set the laptop connection's default gateway to 192.168.0.1 (the PC's address). You should be able to ping the PC from the laptop.
4) Configure Internet connection sharing on the PC. For example, on Windows XP, open the satelite connection's properties panel and check "allow other users to connect through this computer's Internet connection." Follow the wizard if you're not sure how to set this up. When finished, you should be able to ping the Internet from the laptop.
This was first published in July 2003