For the record, because not enough people talk about this stuff...
I nursed M & B until they were 28 months old. I had thought I'd try for a year, or maybe 18 months, but they really loved to nurse, and it was one of the few times when I could snuggle with both of them and just have a moment of relative peace and quiet. Except for the times they were busy hitting each other or putting their hands on the other kid's side. In the end, I had a business trip as a deadline - though as we were weaning I thought it was entirely possible that they'd make it through my trip and then go right back to nursing.
To wean, I tried cutting out feedings when I could - getting up in the morning and going straight to a cup of milk or breakfast at the table, for example. I also started limiting the time we nursed - agreeing to nurse for the count of 10, for example, or for just 2 minutes. Basically, I started putting limits on the nursing as a way to take back some control.
After we weaned, there were still a couple of times that B asked to nurse, and I was generally able to just offer him a cup of milk instead. One time after my business trip he was insistent, so I finally agreed to let him nurse "for the count of two". He got face to face with my boob, then... nothing. He seemed stumped about what to do next. I guess he forgot how. :) That's when I knew we were really truly done.
Now I need to go bra shopping!