Gradual weaning

A couple of my friends are talking about gradually weaning their babies. I will probably do likewise when LB is 18-months old. Anyway, I found this info from a very pro-breastfeeding site I might point them to.
It echoes what I thought: that by about 18 months, you can start to discuss it with the baby so they know what's going on. I also like the idea that you can wean but keep up a feed, particularly the before-bed feeds.