Yes, it was the Speech & Hearing Center at George Washington University, and the training I got there was top notch. But then they told me that I was the fastest learner they'd ever had among their transsexual clients. I graduated in two semesters, and they said everyone else takes longer to learn it. I attributed my success to having been a musician and a linguist, and knowing what to listen for acoustically and phonetically.
What worked best for me was when Professor Moody modeled the voice I was trying for, and then I was able to mimic her accurately. She commands an amazing range of voices. I feel it was just like learning to speak a language: mimicry is the key, which is why little kids are the best at learning languages, they're natural mimics. So I guess the trick is, become ye as little children...