Wi fi cards can be 'good' for the ease at which you can transfer files.. but horrendously slow to transfer.
What camera system doesn't allow tethered shooting?
ie. I thought they all did? in some way.
There are thirdparty programs that allow tethered shooting system, even though the functionality is limited.
eg. LightRoom3(among others) has a tethered shooting ability. It is via cable only tho.
There are dedicated third party programs that may work with your camera.. what camera(system/brand).