Try www.tantra.com There are links to Tantra teachers all over the USA and the world. There are a LOT of other great resources there, also. There are many based in California, and a few really great ones based in Hawaii!
I love in particular the books of Margot Anand, David Ramsdale, John and Caroline Muir, Janet & Sasha Lessin, and of course Dossie Easton and Catherine Liszt. Deborah Anapol's writings are also wonderful, as are those of Wendy-O-Matik. Some of these don't focus on Tantra as such, but I'm sure would be very open to Tantra.

www.ecstaticliving.com are steve and lokita carter who have just signed up as the Skydancing Institute of America representing Margot Anand's work. I highly recommend them. The upcoming skydancing web site will also list Skydancing instructors in the area but really, Steve and Lokita are the best right now. They teach periodic weekend workshops as well as the week long Love and Ecstasy Trainings, (LET), usually up at Harbin. harbin.org

Personally, I'm working my way through a certification to teach Skydancing tantra and I'm giving one and two day classes periodically, although nothing that speaks specifically to separating orgasm from ejaculation. I learned it about 15 years ago in a highly non-traditional way. About all that was really required for me was learning that it was possible. It just sort of started happening by accident after that.

Down in Santa Cruz, there's a group of folks who teach one day classes periodically out of the cultural center. They're represented here on tribe although i don't have a link handy. Their events are posted here or in nearby related tribes.