Originally Posted by DanceMan
There are two methods of wireless in a notebook. Older models could add it by a PCMCIA card, now called pc card, in the external slot. For the last several years notebooks have had an internal mini-PCI slot under a cover on the bottom of the unit. You can buy a mini-PCI wireless card for a notebook that has the slot but didn't originally ship with wireless, or upgrade from wireless B to B/G because the interface is standard.
Your built-in wireless will be from a mini-PCI card. If in a year or two when the new wireless N standard becomes commonplace you decide to upgrade your card, an IBM or HP/Compaq will force you to buy one from them, or modify a regular card at your own risk. The HP will not even boot with the non-HP card installed because of code written into the notebook bios. Dell, Toshiba and Acer don't do this, to the best of my knowledge.