How to geocode a phone number in the United States?

I am looking for a way to get the latitude and longitude coordinates of any area code + prefix land line phone in the United States. Does anyone know of a data provider or service that could be used to do this?

EDIT: I understand that the location of cell phones or VOIP lines probably cannot be geocoded and this is fine by me. I am only interested in POTS phone numbers. Although, it would be nice to be able to identify the type of phone service based on the prefix (if this is even possible).

I found a few options that do the trick for a reasonable price:

Option 1 (web service subscription):

Service Objects DOTS GeoPhone [edit: link is no good now] web service should do the trick nicely. It even seems to provide the "telephone service type" information that I was hoping for.

Option 2 (database subscription):

AreaCodeWorld™ Platinum Edition [edit: link is no good now] is a database product that can be purchased on a one-time basis or via annual subscription. The data spec includes all North American area codes and prefixes along with latitude & longitude coordinates.