My kitchen sink pipe came unglued and as a result, everything that I ran down the garbage disposal, sink and dishwasher, has been going on the ground under my house, for approximately 2 months.
The pipe is fixed now, but smell is still really bad! What can be done to get rid of the smell? I have the crawl space door opened, but that has not gotten rid of the smell.

I guess you will have to go in there and bag up the rotten debris to get rid od he smell. It is still laying around I there.

If it spilled on plastic, remove and lay new.
If it's on the dirt, scrape off the top layer and lay plastic.
Wear safety gear.
Fans might help move the air around.

Try a dehumidifier. That will at least take care of most of the moisture that causes mold. Also like mentioned above, be sure to remove any material that may be lying down there.