. A yeast starter is made by scooping out a cup or two of your wort into a sanitized container about half way through the boiling time. A plastic cup or Tupperware type container will work just fine. You cool it down to around 75° or the optimal temerature for pitching your yeast, just as you would cool your full pot of wort. Then, you add the yeast package to it and wait. In about 30 or 40 minutes you’ll begin to see some action in your wort cup, some foaming and churning. This means the yeast cells are happy and beginning to multiply. When your boil is done, you cool your wort to the correct temperature and pour in the slurry. Now, you will have added more cells than were originally in the package and fermentation will be a bit more efficient. You can also wait up to 24 hours before pitching the starter at which point you should have about 6 times the original number of yeast cells.
This is from the FAQ section of a on-line home brew shop. They prefer to "make a starter" for dry yeasts. Clearly your wasting time and money propagating yeast when it is just that easy.
I had a good laugh at most of their (mis)information.