My son was 2.7 when his little brother arrived. He had already helped me pick out a "Big Brother" shirt for him to wear when he came to see the baby for the first time. He is an absolute nut for sweets, so we had a birthday cake for his new brother and sang "Happy Birthday" when my oldest came to visit in the hospital. He loved that he got cake!
We also had a few John Deere books (he was deeply into tractors at the time) that we gave him as a present from his new brother.