Nope. ISP's don't have "offices" that are specific to areas. An ISP is assigned a block of IP addresses that it can assign to subscribers. Depending on the type of connection an IP may be assigned randomly or sort of permenantly. Dial ups tend to be random and broadband sort of permanent.
For example, if the ISP is SBC/Yahoo, that's all you will know. There is no way, short of a court order, to find out where in the SBC/Yahoo coverage area the user is.
Not sure about what? You don't know how you connect to the Internet?