I have to agree with the other S. - I put up a safety gate at my daughter's door when we put her in her big girl bed (2 years old). I have safety proofed her room, so if she decides to get out of bed and play in her room, there is nothing there that will bring her harm. Often, and after quite a bit of crying, my daughter would sometimes fall asleep on the floor in front of the gate. I'd wait until she was really asleep, and carry her to her bed. She learned in a few days that I was not going to give in, and she started staying in her bed. I would give her a stuffed animal or baby doll and one or two board books to have in bed with her.
We had already done the sitting in her room (which went from just a few minutes at first to over an hour after a few weeks of it!), and my husband even would lay on her bedroom floor until she fell asleep. Unfortunately, that meant he also fell asleep, which really ended up cutting into our time together in the evenings, so we had to come up with something else that would help everyone in the family.
My daughter is 3 now, but for the past 6-9 months, she has tried to "fight" napping, though she really needs it! She's very active and is so crabby by 5pm if she doesn't sleep. Also, when my DD doesn't get the rest she needs, she sleep less - it's a terrible cycle, and lasts for a few days until she just about drops. She'll also get night terrors if she is over tired, so getting our DD to nap and getting her to bed at night is VERY important.
I still put the gate up at night and at naps - it gives me peace of mind that she won't decide to wander around someday.
Hope this helps.