I've no idea where to go for professional threading since it's not really something people do here. I watched the videos and tried out myself and I love it! It doesn't hurt that much compares to waxing. Yay for threading!
I've only ever had my brows threaded - going on almost 8 years now. Use to be the only decent place in Dallas was high end department store spas. Now, there is a great place right outside of Dallas, that is amazing and 1/4th the cost.
For those of you ladies in the DFW Metroplex, there is a great place in Southlake that has been featured on the news, and lots of local TV personalities go there.