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 https://android.stackexchange.com/questions/2516/alternative-to-google-latitude - I want a self-hosted application (on my own server), not on some non-Google third party server