Who makes the Wifi component on the Macbook Pros?
From the SystemProfiler -> Network -> Airport

Card Type:  AirPort Extreme  (0x14E4, 0x8D)
Firmware Version:   Broadcom BCM43xx 1.0 (5.10.131.42.4)


Vendor ID 0x14E4 is for Broadcom http://www.pcidatabase.com/vendor_details.php?id=767