What do you mean by a "wireless card?" You mean wi-fi? If yes, then you might want to look at embedded wifi adapters like: http://www.dpactech.com/wireless_pro...ess-module.asp or mini-pci or compact flash.
Or serial like this: http://www.dpactech.com/wireless_pro...ial-bridge.asp
Finally, if you have the stomach for it, you can build a USB host for the 68hc11 using a cypress SL811HS USB Host adapter controller. Only a few external parts are needed to get it up and running hardware-wise.
Come to think of it, it might be the easiest to do ethernet and use an ethernet to 802.11 bridge (like used on the XBOX)
Of course, the hardware part is always the easy part, the software is the real PITA.
Now if you just need a wireless point to point connection, check out http://www.sparkfun.com/ for some nice wireless serial modules.