We are going through the same thing right now. A couple of things have worked for us, but I must say, my son is still in pullups!
We let him run around bare bottomed as much as possible in the evening, when we're home from daycare. He seems more willing to use the potty if he doesn't have to mess around with clothes. (One of the signs of readiness is able to take pants off and put them back on and he fails that test miserably.)
I tried a reward system... if we put you on the potty, you get an m&m no matter what happens, if something comes out, you get a sticker, and if you TELL us you need to use the potty, and you do and something comes out, you get to go to the goody bag. I stocked an old tote bag with goofy toys from the dollar store and Christmas Tree Shop etc. The goody bag was the only real bribe that worked, and we stopped with the m&ms and stickers. And then we got to the point where he has to use the potty 3x before the goody bag, and now he's sort of lost interest again.
I'm pretty sure we're going to have to resort to a cold turkey approach - ditch the pullups and to to underpants. He doesn't mind a wet diaper, he doesn't mind an accident if he's naked but he hates the wet underpants. The problem is we have every weekend booked from now 'til mid-December, so I'm deferring the potty training boot camp weekend for a bit.