Well My nearly 2yo spent his first night in a single bed last night and he was soooo proud of himself (so was i). We made a fuss of him and he helped to pack the cot away and put it in the other room for the new baby, and went shopping all together and he chose his quilt cover and sheets, then he helped me make his bed up. I was surprised that he actually slept ALL NIGHT in there, and wasn't even in a hurry to get up when he woke up. Usually (well i mean every night lately) he ends up in bed with us at some point during the night.
Oh, we've also had one side off the cot for a few months now so he's been used to being able to get in and out by himself.
Good luck!!