[postgis-users] distance_sphere() with polygons

[Daniel Ricard]

Hello all,
Is there a trick to using distance_sphere() or distance_spheroid() when one 
wants the distance between a point and the boundary of a polygon?

I've been using:

SELECT distance(i.the_geom, boundary(j.the_geom))

and would now like to obtain distance in meters instead of degrees.

The documentation say that distance_sphere() and others only work for points 
but there must be a way to do this. Help greatly appreciated. 
Cheers,

Dan