You could already write your own apps using our API (see documentation), but if you prefer the JSON format than you can now use for example https://secure.trackmypeople.com/api/status.json instead of https://secure.trackmypeople.com/xml/status.

Please note that some xml responses have changed, so if you were already writing an application then you better use the new xml-url, which is https://secure.trackmypeople.com/api/$action.xml, where ‘.xml’ may be ommitted.
All old xml responses remain the same if you use the old url: https://secure.trackmypeople.com/xml/$action, but it will become deprecated and the new responses contain more information.

As always further suggestions are welcome at info@trackmypeople.com.