Putting a safety gate up is a great idea. Do you use a safety rail as well? This may help him feel secure.

My eldest DS made the transition when he was a month off two. I set the bed up in his room with him during the day and got him to play in it and "pretend" to sleep. I explained to him that he will sleep in it tonight and made it sound really exciting. I also prewarned him that he couldn't get out of bed unless mummy or daddy came and got him. That night I repeated the no getting out of bed bit and put him into bed with a routine of book and cuddle. He cried about being left alone so I hopped in beside him. He went quiet, but wasn't asleep. But then the phone rang!! I had to go get it because DH wasn't home and after a while I realised my DS wasn't crying so I didn't go back in after the phone call. After that I never had a problem with him sleeping in a big bed and he still at the age of three does not get out of bed unless we tell him he can.

I don't know if we're just lucky or if it is because I explained things to him first, it is amazing what they understand, even if they can't verbalise it.

There have been some great suggestions by the other girls on here, I hope you find something that works for you soon!