We had exactly the same issue - the toddler who never got tired! Our lovely DS would be roaming around, smiling, chatting and completely fresh at 8.45...9.00..9.15, even if he had been undressed etc.
But also, ignore anyone who is smug about 'oh my child goes to bed at 7.00 on the dot'. All children are different and some have a later sleep cycle than others. Whatever we have done, DS has never been ready for sleep at 7.00! Even the posts on this thread show that children's bedtimes are culturally determined - I believe it is very common in southern Europe for children to stay up late to have supper with their parents?
What helped us with the time of going to bed:
DS deciding not to nap anymore in the daytime - this happened at about age two and a half. As soon as he shows signs of cutting out that nap, go with it. He will fall asleep in the late afternoon for a couple of days, but sooner or later it will stick.
Getting into the habit of doing things earlier. If you know he is not going to sleep until later, it is very tempting to let the pre-bed pattern slip later.
Everything needs to be earlier- his suppper, your supper, bath...
Needing to wake him up earlier for nursery.
What helped us with going to bed by himself:
Moving to a bed and making sure that he fell asleep in that bed. I started by moving him to a mattress on the floor in his room, then lay down beside that with him. I then introduced the bed base. He liked the fact that it was his bed and would climb in there quite happily.
A miracle CD. It is very, very gentle and called 'Lullaby' from Amazon.
We started off listening to that on our double bed, then moved the pattern to his room as above.
Gradual retreat. I started off lying right beside him (often bf too), then gradually moved to a little further away, then by the door...
So, shortly before two he was being bf to sleep on my lap :) but going though the steps above, by age three he was getting into his own big bed willingly himself, I would say goodnight and then sit outside his bedroom door (on MN!) for 10 -15 minutes until he was asleep.
Now he goes up to bed and I just tuck him in and wander off! This might seem slow progress to many, but he has never been left to cry and is always really happy to go to bed, so I am happy with that.