I understand your hesitation in calling.. but I still think that you should consider it. Besides.. do you know for a fact that they have internet access at home? Its a possibility that they don't.. or maybe they have dial-up and they want to keep their line open.
One day of waiting won't hurt the situation in the slightest, but I would still consider calling them if they don't call. You never want to assume what the other is thinking.. they may be nervous to call you and don't want to come across as 'bothering' you!
... and like always.. keep us posted!
