I've recently bought a 2nd generation iPod Touch, and I'm getting used to the location finder (without GPS).
However, my home router's seem to enjoy hiding the location... I've googled the issue, and I've come up with the WPS notion, and a link for a form where we can tag a given MAC address (your router's) to a easily findable (via a Google Map widget) geo location. They say I have to wait a while before that starts to work. We'll see... :)
From the Skyhook's website:
The WPS is an essential part of any complete Location System. Without this capability, the location of a mobile device cannot be accurately or reliably determined, especially in indoor or dense urban environments. As a key component of XPS, the Wi-Fi Positioning System (WPS) has been closely integrated with GPS and cellular positioning.
More info and the aforementioned form can be found here.