If you want to stockpile laundry soap, a few things to be aware of (and I live in a very hot, humid environment, so some of my points may not apply to you).
Powder laundry soap will cake up into concrete if you don't take precautions to store it properly.
Put it in plastic restaurant buckets with plastic lids, and seal the lids with a bead of clear silicone sealant. You might also consider putting Damp Rid into the containers just before you seal, and store these containers out of direct sunlight.
Keep in mind that you want to be careful with certian types of laundry soap if you have a septic tank and if you use well water.
Certian substances (like phosphates and dyes) can leach into groundwater and find its way into streams and ponds, which can affect wild animals and, therefore, your food supply.
If these issues are a concern (and--in my mind--they should be), then get Seventh Generation laundry soap...which cleans really well and is safe for the environment.
I hope this helps you.