Some flamenco technique
If you haven’t been to Miguel Bengoa’s flamenco site do yourself a favour and check it out. Some great lessons on flamenco technique can be found there. Miguel clearly discusses and delivers advice on the following techniques:
Alzapua and tremolo are also covered.
There’s a whole variety of technique lessons available at flamenco-teacher.com. Some are free and some you have to pay for.
And I really like newlearningvision.com. This is Adam del Monte’s home and he offers quality flamenco guitar lessons that are technique-rich.
If anyone else has any more helpful technique links please add them as a comment!

yes, Adam del Monte’s site is pretty good — I have taken a few classes. Check out my site as well — myflamencoguitar.com. I have interactive sheet music exercises and flamenco material.