The most easily purchased wireless link for a digital camera is an EyeFi memory card, which can be made to create a WiFi connection to a computer or a cell phone. The device sounds like a wonderful idea, but it's less than wonderful in practice.
The EyeFi uplink essentially needs to be sent through a router to connect with a computer, and that router needs to have internet access at all times - because the EyeFi software insists one being able to connect to an EyeFi server.
It takes some effort to get an EyeFi card to connect to a computer, and even when that connection works, it is far, far slower than a cable link. By a long shot, the best way - the only fast and reliable way - to connect a DSLR to a computer is still through a USB cable.
Now, those who are adventuresome, patient and have the right sort of USB EVDO modem may want to experiment with a battery-operated router and an EyeFi card, but don't get your hopes up or expect miracles.
Apparently you didn't check out the thread I linked to. The wft-e4II grip looks more promising, although it's expensive. I've come to the same conclusion you did with the eye-fi cards. Even with the grip it requires shooting Raw to card and sjpg to the computer for viewing if you want speed. I'm sticking with the cable for now.
One correction to that thread, Canon now has a fix for utilities and OSX Lion.