GeoDjango / PostGIS - Cut geometry by bounding box

Question

I am looking for a solution to retrieve the geometry(ies) from a polygon/multipolygon within a bounding box in a GeoDjango application.

The application I am developing has a requirement to serve out tiles of geographical data, and many of our geometries are very large and span across multiple tiles. To reduce the payload of each tile I would like to splice(cut) a geometry shape(s) from a bounding box.

I am storing Planet.OSM data in a PostGIS database.

Any suggestions would be greatly appreciated!

Thanks