Yes, I am still waiting. There is no time limit even if they may tell you it will take 9-12 months. I had kept inquiring my status twice every week sice 04/2004 and they sent me a letter in 10/2004.
I think that we got the exact same letter and I can assure you that you have 99% chances to be under background checks.
It will take 1-3 years to finish background checks.