Bob - I would be totally honest with them and contact them asap to see if they will consider a late application (phone is better than email if you have a contact number. Don't try to come up with some excuse to explain away the fact that you are late. Express your enthusiasm for the position and ask them very politely to consider a late application.
If you have the necessary qualifications and would make a good candidate for them, then there is absolutely no reason for them to turn you down. Like suggested, email with your application attached immediately and follow up with a call.