personally i'd go with the Alfa 500mW USB Wireless B/G Adapter. It has a realtek RTL8187L chipset which works fine for injection.
But you mentioned you wanted a pcmcia card, so i'd suggest you check out the following link:
http://backtrack.offensive-security....s#PCMCIA_Cards

or maybe even the following discussion, which will either have you more confused or will help you decide :
http://forums.remote-exploit.org/showthread.php?t=2191

Do tell us what you finally decide on and your feedback on it.