@ihans: What exactly is "very fast" for you? I doubt any macbook is going to suddenly make the camera faster at sending data. I know my computer isn't the weak link.
@M.ST: That's what I do under most circumstances, too, but the point of tethering is that you don't have to keep pulling cards to dump files. That slows down a shoot, making your clients wait to see their files on a big screen.
@Mwindley: All I did was use the connection wizard and set up the connection, just like it outlines in the LAN manual. It seems like you HAVE to use the wizard. If you just try to set it up manually it doesn't look like it ever runs the test at the end to confirm that it can connect, and then it'll never work.