C.G.
All this pandemic talk is alarming but try to remember- the chances of getting the regular flu are infinitely higher. If your son had regular cold symptoms like he has now you wouldn't panic about it possibly being the flu, so try not to panic about the swine flu.
As far as catching it, it is contagious about 1 day before and 7 days after the symptoms appear. If he hasn't been in contact with anyone who has come down with swine flu in the last few days there is really no reason for concern.
I have to admit I have been nervous myself about taking my kids to day care, but once I read about the Swine flu I feel much better. Here is a link to the CDC info: http://www.cdc.gov/h1n1flu/swineflu_you.htm