If you have a smartphone there are applets that can post your gps location to websites - such as the iphone loopt or glympse or instapaper or google's latitude.. those systems require the phone to have gps active and allowed to send updates to the tracking database. most are limited to friends that you have allowed.If he had access to your phone he could have installed those or set it up to allow him access.I don't know anything about the "skype phone" tho.
I found two applets for the Skypephone; "spime" and "Skype Geo Locator" that you might want to check your phone for.
Mobilspionage
