Here is a list of what you will need:
1 bar of soap (some folks suggested Fels Naptha, I used Dial)
1 cup of Borax
1 cup of washing soda
a big pot (that holds more than 2 gallons)
a long spoon
2 empty gallon jugs/containers
I purchased all of the ingredients at Wal-Mart (they are all on the laundry aisle, except the dial soap). I don't remember exactly what it all costs, but I'm certain it was less than $6 for everything, and I have enough Borax and Washing Soda for a few more batches.
The first step is to grate the soap.
Once the soap has melted add the washing soda and borax. Bring that mixture to a boil. Once it is boiling and all mixed together, turn off the heat and add 1 gal cold water.
Pour your soap mixture into your containers. I had a milk jug and an old fabric softener jug.
When it cools, it gets THICK! I didn't realize it would do this and I had some problems getting it to come out of the container at first. After shaking it up REALLY well, it works great now. I would suggest you just leave the mixture in the pot you used to cook it in, and let it cool completely. It might even separate a little, no big deal. Maybe leave it there overnight. In the morning, use your spoon to mix the laundry soap up really well, then add it to your containers. This way you don't have to try to shake the soap after it's in the container.
Use about 1/2 cup for each load.
My clothes are clean, and they smell good (sort of like the dial soap I used). Next time I will try a different soap scent to see how that works.
This would be great thing to have if you or one of your family members suffers from sensitive skin issues. Just use a cheap bar of bath soap made especially for sensitive skin.
I've never really used fabric softener for anything except our sheets. I know, sounds crazy, but I don't like that heavy perfume smell that most fabric softeners leave on your clothes (and when you start running or sweating, that smell is MAGNIFIED and it gets to be way too much). So this detergent is pretty much the only thing we use on our clothes now.
If you have any questions that I didn't answer, leave a comment. I'll do my best to respond to your questions.