I have registered at PEK. You have to do it on entry - right after passport control there is a raised desk. Ask there - takes 10 minutes - short form, thumbprints, etc. It is easy.

It should work on entry AND exit from China, which is huge (for those of us who often wait in the line to exit). Having said that, I have tried it twice and it did not work - yet. On exit last week, they told me my passport was fine, but that my boarding pass was not. I think my error - I printed the BP at home and should have done it at the check in so that my papers could be validated by someone. Will try that again this Saturday.

On entry couple of days ago, the eChannel machines were out of order - oh well. I will keep trying, it should work and will be very valuable.

(One note - when it did not work on exit, the guard was nice enough to take me to the front of the APEC line for the person to handle ASAP, so it still saved me a boatload of time).

Best of luck with this, it is big.