Many contemporary Tantra teachers were trained by Bhagwan Shree Rajneesh (Osho) or his disciples.Bodhi Avinasha and Margot Anand are two of the best known of these teachers. Sunyata Saraswati, co-author with Bodhi Avinasha of Jewel In The Lotus (still the best self-teaching book in my opinion), also trained many teachers, as have Charles and Caroline Muir. These are some of the names you will probably come across when evaluating the credentials of prospective teachers.
The single best source for listings of Tantra teachers is the Teachers Directory at Suzie Heumann's website Tantra.com. Teachers are listed both alphabetically and geographically. Tantrika International, founded by Bodhi Avinasha, also has a geographically organized teachers directory, as does Charles and Caroline Muir's Source School of Tantra. My own Tantra teacher since 2001 is John Hawken, a student of Margot Anand, who teaches at Skydancing Tantra UK, and in the Chzeck republic.
When personal Tantra instruction is either inconvenient or too expensive, Al Link and Pala Copeland'sSexual Mastery Course and Kerry and Diane Riley's Ultimate Home Tantra Course are two excellent self-teaching courses. I highly recommend either of these courses for those who can't find a local Tantra teacher, attend a Tantra workshop, or just want to explore Tantra in the privacy of their own home.
If you're interested in finding out more about Tantra, the books, courses, and teachers are there for anyone who wants to learn. You can even use my blog and other websites to get started. The most important thing is to get started, and "when the student is ready, the teacher will appear."