The lightweight “Midori” web browser supports “geo:” URIs natively since version 0.3.6. Here’s the respective release announcement (from May 2011, only discovered now):
http://mail.xfce.org/pipermail/xfce/2011-May/028718.html
The browser extracts latitude and longitude from a geo: URI entered or clicked on, and redirects the user to the respective location on OpenStreetMap.
Very cool.
