I JUST DID IT 3 WEEKS AGO- THIS WORKED!!
My 2 1/2 y/o son was ADDICTED to it, I had him down to where he only had it during sleep and nap, but he still would ask and get it occassionally during the day (car rides, when in his stroller, etc.). I tried hiding it, acting like they dissappeared, but he's way too smart for that. He also could not fall asleep without it - PERIOD.
Well, 3 weeks ago he had the sniffles and couldn't sleep b/c he couldn't breathe through his nose OR his mouth b/c of the nunu in his mouth. So, several moms told me to throw it away, I tried it... he went straight behind me and DUG it out of the trash... then I totally lost it, I went all out and gathered up all 6 of them and one by one cut the nipple completely off infront of him. (This was a last resort, I was really NOT wanting to do it but I could think of nothing else.) **This was for his mid-day nap, not at night, I think that helped**
Anyway, he screamed, turned purple in the face, shook like he was seizing, and even hit me in the legs which he's never done. I tried to lay down with him but he screamed for an hour. Finally he wore himself down and I let him take a toy to bed and then THAT WAS IT. He's not had it since. He asked a couple of times the next few nights but not anymore has he even mentioned it. I was expecting a meltdown that night at bedtime, but TO MY SURPRISE he only asked for it maybe twice, and I told him "You remember, they're all broken?!" and he never asked again.
I reccommend doing it in the daytime, I wouldn't want all that drama at night. He even sleeps the whole night through and sleeps better now!!!
Good luck, I know it sounds harsh, but it works! I even tried having him give it away to the easter bunny, etc, but NO he's too smart for that. I even kept the plastic ends as a reminder for when he'd ask and I'd let him SEE that they're all broken.