Cardbus is a 32-bit standard that is backwards compatible to PCMCIA. Most laptops made in the last 4-5 years have Cardbus. To make sure you can go to Control Panel, System, Hardware, Device Manager, PCMCIA adapters and see if you have a CardBus controller.
To make it simple
For older laptops use PCMCIA, newer laptops (Pre-Installed with Win 98 and above usually) you can use PCMCIA or CardBus
To make it simple
For older laptops use PCMCIA, newer laptops (Pre-Installed with Win 98 and above usually) you can use PCMCIA or CardBus