I applied online. The process took 4 months. I interviewed at ETS
Interview
There was no explicit interview aside from submitting your application and waiting to hear back (the wait period can be very long--I waited over four months to hear back from one). After that, if it's your first test with them, you fill out the new hire packet, sign up for a training session and take your qualifying test for the particular test you'll be rating for. Painless except for the wait.
Interview questions [1]
Question 1
These are the training and practice tests you take to prepare you for each test you score. Training time is variable for each test, but generally appropriate to the difficulty of the content scored.
I applied online. The process took 3 weeks. I interviewed at ETS
Interview
The process was quite simple actually. I simply provided resume when I applied. There was not a great deal of paperwork and it was all pretty straightforward. They gathered all the info they needed from me via email.