Warning about Borax:(personal experience)
Some rare individuals will experience burning-itching sinuses, face-skin, eyes, and/or respiratory irritation when exposed to Borax. This irritation usually comes on slowly (hours or days) and gets more severe with time. So severe, that a sensitive individual will react from being in the same room with a single piece of laundry washed with Borax containing soap. The rinse cycle does not remove all of the Borax and sensitive individuals will still react to the laundry, even at a distance. I'm telling you this stuff can become like tear gas to some individuals. Sensitivity to Borax is rare, but it is bad if you have it.
Please pay attention especially if you have children. You may mistake the symptoms for a cold or ordinary allergies and they will only get worse if exposure is not stopped. If someone in your home is found to be sensitive, all laundry will have to be rewashed with a different soap/detergent, laundry baskets will need to be rinsed with water, inside of dryer needs to be wiped thoroughly with damp cloths and you might need to do the same with closet shelves and drawers. I suggest experimenting before contaminating you whole house with this stuff.
You can try making the laundry soap without the Borax. It will loose some of its cleaning power. I've read somewhere that baking soda can be substituted for the Borax. Just experiment with ratios.
EDIT: I'm not trying to discourage anyone from making soap. I don't doubt the recipes mentioned in previous posts clean very well. I know the batch I made did, and was very inexpensive. Sensitivity is very rare, but can become severe if not recognized and dealt with.
