If you prefer liquid laundry soap, here is the recipe.
2 cups of grated soap (I recommend Pink Zote)
1 cup of Borax
1/2 cup Super Washing Soda
1. Put the soap, plus 2 or three cups of water in a medium saucepan and heat over medium until dissolved. 2. Stir often.
3. Once the soap is dissolved, remove it from the heat and add the other two powders.
4. Stir again until it is dissolved.
5. Pour into a gallon size bucket then add enough hot water to fill the bucket.
6. Let stand overnight.
It will have a gel-like consistency.
(picture taken from "Little House in the Suburbs".com)
If you are using Zote - one bar should be sufficient.
You can make up to five gallons (or more at a time) if you have a five gallon bucket. Just adjust the measurements as needed of your ingredients.