I ordered a number of Optiplex 745 small form factor pc's and tried to ask for a wireless solution to go with them. I was told that Dell recommends a USB wireless device that clips on the top of the case.
At any rate, I ordered the PC's and already had a medical PCI video adapter that needed to be installed in the PCI slot. That left me with a PCIe x16 slot.
Luckily, I was able to find a progressive company that made a PCI express (PCIe) x1 card that works with the second slot in the machines. I don't know why there is only 1 manufacturer for the new format. Apparently you can reuse the same driver code and need only change the hardware (http://en.wikipedia.org/wiki/PCI_Express). Maybe this is a chicken and the egg problem.
Dell should really offer to sell these Abit AirPace Wi-Fi cards.