If you are leaving him because you have to go to work or be somewhere at a particular time I'd go early so you can BOTH settle in to it and you can leave him Happy.  I didn't have to be anywhere (4 hours a week for other kid interaction mainly) and I too have worked in Centre's in the past and I found that I was sad enough as it was, had I left her crying it would have been much much worse.  Kindly the gorls offered to ring me during her session to let me know how she was going & they did & it was a relief.  I did pick her up early though as I didn't know what to do with myself LOL.  I still tip toe around thinking she's asleep because she's not under my feet LOL, have to keep pinching myself...I have PERSONAL SPACE.

I also wrote a list of things "we"do and she preffers & her words so they had a clue as to what she was saying.  Things like we don't allow walking (or crawling in our case) with food or a bottle, I don't want her doing that at day care either, (I don't think they allow it there, but just in case), I told them her fave songs incase she gets upset or hurt & needs distracting.  I pack her "snuggley wuggley =Blanket Bear) so she feels better about going for a nap.  I always have her wearing something of Dorothy the Dinasaur because she is her fave thing in the universe & it's a great distraction & comfort to her.

Good Luck, it is probably going to be heaps harder on you than him, if you aren't going to work, go visit someone or get out of the house would be my suggestion, you tend to dwell on missing them a bit at home.

for my son's first day i stayed at the childcare centre to see how they intrected with him and to see how he liked it it made it alot easier for the following few weeks