Mine is a Cisco card (I would have ordered Intel, but they were out of stock on that), and I coerced them to sell it for $75 to me. Works pretty well - no complaints. I suspect the Intel card would work just as well, but I can't be sure.
Important: Be aware that you need a precision toolkit (precision phillips screwdriver or preferrably two of different size) and a razor blade (to remove stickers on the screws holding the wristpad) to install the card. You'll want to look at
T40 hardware maintenance manual. You need to remove the battery, keyboard, and the palmrest/touchpad cover before installing. The card goes in a socket like a SODIMM socket, but you have to also connect the antennas and route their wires. The slot for the card is directly below the touchpad (and directly above the south bridge on the motherboard).