They are Ultra Low Voltage (ULV) Intel Core Solo CPUs, models U1300 (1.06GHz) and U1400 (1.2GHz). These were mentioned last year in some of the roadmaps and they seemed on-again and off-again. According to DailyTech, these CPUs were under a press embargo until April 16.
Now while the NX100X page isn’t up at Gateway (it might be now), the E-100MB is up, although you have to search for it, and it’s listed in several places (business, education, etc.).
Edit #2: Digg has picked up on this and has some interesting comments about battery life and Intel CPU releases.