From Dan Barenblatt:
There are natural, nontoxic ways to get rid of bedbugs (cimex lectularis, used as a germ warfare vector by the japanese against china civilian populations in WW II):
1) Spread diatomaceous earth powder–available by mail order or in selected stores*–around your infested dwelling.
2) If you can stomach it, collect spiders and/or centipedes, and set them loose in the infested dwelling. they will eat up and drive out the bedbugs.
3) A combination of 1 and 2.