Re: Distance Key/Legend Thing ...

It is an undocumented (but announced by Google) control called
GScaleControl.

Here is the thread announcing it:
http://groups.google.com/group/Google-Maps-API/browse_frm/thread/fd13970c95e8d5c3/c9beb5938b61f2f6

to add it to your map you do this where you add the other controls:
map.addControl(new GScaleControl());

-- Larry