UTM or Latitude-Longitude coordinates available in OpenStreetMap?

There are many many way to do this. The first three that come to mind:

• Use the www.openstreetmap.org website and hover the mouse pointer over the "permalink" link. The status bar in your browser should display the URL of the current map view which includes latitude and longitude of the map center. Or click the "export" tab which allows you to draw a rectangle on the map and see its edge coordinates.
• Use the www.informationfreeway.org website which offers a fullscreen map view and a coordinate display for the position of the mouse pointer in the lower right corner.
• Use the gll.petschge.de website which offers a crosshair at the center of the map view and a coordinate display at the top of the page. If you sufficiently bribe me I might even add a coordinate display in UTM.

Another possibility would be to create a small page with openlayers using Openstreetmap tiles and and a MousePosition Control.

In the editor, press CTRL+SHIFT+L to display the Location Panel.

If you are using the editor potlatch 1 you can get the location coordinates of the mouse by pressing the l-key. Don't know if such a key exists in potlatch 2 though - the help does not state any...

You can try to use (software name removed) from (link removed). You can browse Google Maps, Bing Maps and OpenStreet Maps and see mouse position coordinate both Lat/Lon and UTM in the Datum of your choice.