When this happened to me, I called a repairman and they found the hose clogged with dirt. So the wash cycle didn't get all the way drained and it wasn't noticed until the rinse cycle still had water in it. Then the OTHER time it happened, I noticed the wash tub had broken off and slipped down and it wasn't getting good traction to spin right. So check the hose for mud and check the tub screwed up around the lip of the tub and see if the tub has broken off them.
It could be that the machine is clogged and that is why it is not draining. If a hose has kinks, try to uncurl out the kinked hose. You can also check if the lid is properly closing all the way, or check if the belts are loose. Check out http://www.ehow.com/how_5030854_fix-machine-not-drain-spin.html for more information.