L.,
I feel your pain. I am in the throws of potty training my 2 year old and he is about 75 percent there.
One thing I found very helpful is The Potty Bootcamp. A mom combined various methods into a quick read download. It is only $5.95 and took me all of about 30 minutes to read.
What was most helpful for me was "the week of preparation". I had never really thought to explain to my son that pee pee and poopy belong in the potty (I didn't have to do this with my daughter). I also explained to him that he is a big boy now and only babies wear diapers. Finally, and it was tough to do but it really worked, I let my son pee his pants and poop in his pants and then let him stay in it for a bit. My son really hated this. He wanted those pants off! Then when I took them off of him, I had HIM put the poopy in the toilet and wash out his underwear. I thought the author was out of her mind when she recommended this, but my son only washed out about 2 pairs of pants and he started going on the potty. Adding to that rewards for going in the potty, telling me that he had to go and going independently on his own he is really doing well.
I only had to use negative reward once as well. My son stood beside the potty and pooped in his pants. He did not get to watch any cartoons and lost his bear for a time. Again, he has not done this again and had been pretty consistent about using the potty. This is not to say that he does not have accidents, but he is making every effort to use the potty and doing great!! I also strongly recommend the book "Everyone Poops" By Taro Gami. My son loves it and it seems to have really "clicked" something for him.
The Potty Bootcamp may seem extreme to some parents and I'll admit that I did not do all of the "drills" (but my son had been working on pottying for a while and they weren't needed). However, in terms of speeding up the process, I can't recommend it enough and I am very happy to be only using pull ups for sleep.
Good Luck!!