Try this for starters:
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1042026&CatId=109
The downsides to this one is that you have to reach around the back of your computer to add or remove a card.
It's really designed more for install-and-forget uses
(like a PCMCIA WiFi card for your desktop computer
). They make
(or *used* to make
) ISA to PCMCIA adapters that had a front bay, mounted in a 3.5" drive slot.
(I may even have one shoved in a box somewhere - not that it's very useful any more...
) I assume they make a PCI to PCMCIA adapter that is also front bay accessible, but never really seen one.