Ds is 2.5. For a while we've been modelling going to the loo, sitting him on potty when changing, he's done wees and the odd poo (accidentally) and nursery are doing the same.
We've found he can do a wee and a poo if nothing on in the house with just some reminders. With pants on we get accidents.
I wasn't keen on chocolate rewards and he was initially just proud of our pride! However after he has seemed confused over pants or bare bottom ive started offering chocolate fingers if one in the potty. (Bare bottomed!)
I'm intending to keep this going and then see if he can do the same with a nappy on (he's very capable of taking it off, more easily than pull ups or pants and has been telling us its full of wee. Did same with poo once! 
)
What do you think?
Wasn't sure about chocolate due to not getting it at nursery. They say they spot when a child is ready. And do potty learning. Which is fine, I like the concept- in fact I wasn't going to do anything except he surprised me with the wees and pops when naked in the heat!)