Answer:
Now we are past the silly answer, the correct answer is the local flight service station (FSS). You can call them by phone or by radio. For example, the FSS for the area where I live (Phoenix AZ) is at Prescott airport, phone (928) 778-0314
There are various frequencies which are remoted to various VORTAC facilities, the frequencies for which are as shown on Terminal Area and Sectional charts.
These FSS's are run under contract to the FAA by Lockheed, Martin Inc