Here's a article I got from AskDrSears.com ( I love this site) and of course every person has their own opinions and their own way and this is their way (his family is a fan of co-sleeping)
HOW CAN I TRANSITION MY 3-Y-O INTO HIS OWN BED?
"My three-year-old won't go to sleep in his own bed. He still wants to sleep in our bed, which we have done for three years now. How can we transition him into his own bed?"
There are two steps to this transition.
First, buy a toddler bed (one that uses a crib mattress and is low to the ground) and put it next to your bed. Make this a fun trip to the store and let your child pick out his "big boy bed." Put him to sleep in his new bed. You may need to either lay in your bed next to him or sit on the floor next to his bed. Expect him to want to crawl into your bed when he wakes up during the night. You can either allow this, or place him back into his bed and shush him back to sleep. The most important aspect for him to learn at this stage is not to stay in his bed all night, but rather that he has his own bed and he starts the night in it.
The second step occurs when he is comfortable with his own bed. Now you move the bed into his room. This may be a matter of months, or it may be a year or three later. Again, you put him to sleep in his bed. He may wake up and stumble down the hallway into your bed. (My eight-year-old still does this without even waking us up. We wake up in the morning a little squished, but it is nice to be able to snuggle with him on occasion). As he gets older, he stays in his own bed through the night more often.
If your child is still coming into your bed a little too often and you really want it to end, you can try a sticker chart reward system for every night he stays in his bed.
As with all stages of a child's life, they grow up way too fast. A few years from now he isn't going to want to snuggle or hug, and you will miss those warm mornings with all of you waking up together. Try not to be in too much of a hurry.
Dr. Bob