DS weaned at around age 3.5. Very gradual--he went from 2x a day to a couple times a week to every couple of weeks to....well, guess he weaned! (He will be 4 next month.)
He did tell me several times in the last few months, "Mommy, I'm weaned!" (even though he was still nursing occasionally.)
I remember telling him what weaning was when he was around 2.5, and the look of sheer incredulity on his face. Like, "WOW, Mommy, why would anybody do THAT???" But he did it.
He still gets that old besotted look if he sees me getting out of the shower or something, and he still uses a pacifer, so I guess he's not totally weaned...but. It was completely painless. I was sad thinking about it when he was 2, but by the time he was 3.5 it was like I was forgetting about it too. The nursing relationship really does take two people.