Is there a (decentralized) open source "Google Latitude" alternative? Is there an open source application which allows to share my location in real time? I'm looking for a fully open source solution, that is open source client as well as open source server software.

It doesn't have to be scalable or anything, I just want to share my location to whoever has the link to the application on my server.

This is not a duplicate of Alternative to Google Latitude? - I want a self-hosted application (on my own server), not on some non-Google third party server
OpenGTS provides fleet tracking, and there is a (paid) Android App on the market.  Given that it's open source, it's always possible someone (you?) could develop a free app as well.