I have a 2 year 7 month age gap between my two children, the youngest is now 5 months.
We started by buying a new bed for our first and getting him excited about being a 'big boy'. We also talked alot about the new baby, even praying for her each night.
Before going to hospital we told him that mummy was going to go to hospital to have the baby and we were lucky enough that my mum come over to stay with him for the week. So that was exciting for him.
After having the baby, on his first visit we gave him a present from the baby, and he gave one to the baby (That he helped choose before a teddy bear) He came to the hospital every morning with my husband for two hours and we gave him something special each time, he also bought a dvd to watch. he then went and did special stuff with Dad in the afternoon.
When we came home, he got to 'help' with special jobs. And we made sure when the baby was sleeping I had special one on one time with him.
WE only had a few days of him bieng a little clingy but on the whole he has loved having ehr around. She now gives him big smiles whenever she sees him and he just loves touching, cuddling, kissing, playing with her!!
Hope that helps.....