The February 2006 issue of WIRED magazine mentioned in its NXT coverage four individuals who were brought on board as the first members of the User Panel. Three of these individuals have dedicated websites (see below):
John Barnes: -With the converter cables mentioned in an earlier post, most (or all) of the custom sensors on this website should be compatible with the NXT. Check out the Ultrasonic Range Sensor - look familiar?
Steve Hassenplug -Steve invented the Legway. If you haven't seen it, click here. The NXT version is probably around the corner.
Ralph Hempel -I couldn't find anything here regarding NXT, but it won't stop me from checking back now and then.