Just read this tip. Use clip hangers. I haven't tried, but maybe it would be possible to keep 2 pairs of boots on each hanger. Depending on the type of clip I would perhaps use some sort of padding (fold a piece of fabric or maybe cardboard) to keep the clips from leaving marks on the boots. Single clip hangers are also available, for 1 pair of boots.

http://s608.photobucket.com/al.....8;newest=1

Here's another type of hanger for 1 boot:

http://s608.photobucket.com/al.....8;newest=1

I'm getting more ideas. You could hang from a rod, or individual hooks. Maybe you could even hang your boots on a wire with regular clothes pins...