contours as polygons

I have a number of different tools to create contours as lines from a 
surface.  Does anyone know of a tool or have some code that will create 
polygons instead of lines when contouring a surface?  Each polygon would 
represent the area between n1 and n2.  I have the ConRec code and 
thought about writing this myself, but it gets complicated with donut 
polygons.  I bet someone's done this before.  Maybe there's a better 
mailing list for this question?  Thanks.

Bryan

Bryan Keith
GIS Specialist
Geomega, Inc.
Boulder, CO, USA