Buddy goes to daycare, but I started him there as soon as I got him - at 3 months old! He was the tiniest baby there - but this particular daycare is *wonderful* and they really help with training.
Did you talk to the people at daycare about perhaps spending some time helping to show him the correct behavior?
Is there another option for daycare for him?
I feel really lucky to be here in the Bay Area - not only do we have lots of options for daycare, but the one that is closest to me is the most reasonably priced and the most conscientious one around.
http://www.everydog.com
Good luck with your little man! And I agree to watch Cesar on the Dog Whisperer - he really does focus you on yourself to see what you might be doing to encourage the behavior -