Chicho - Congrats on the young one going into his first day of preschool! Those are fun times. My son is 9 1/2 now, and he still remembers all of his friends and teachers from preschool.
One thing that has helped us when Amerasia was at home, and I was at work, is exchanging an email or text or two throughout the day, just letting each other know what we've been up to, and how our day is going.
I hope your son has an awesome time!!