Acacia powder is more commenly used for stomach problems, but it is also a great resist. I had trouble finding the stuff here locally, so I bought it through Amazon.com. This was the first time I used it, but I will be using it more often in the future.
To make the resist you use half powder and half water. I don't know how long it stays okay, but I had mine in a container (outside the fridge) for more than a week. I used this coaster as my stamp:
Applied resist on it and pressed it down on the fabric. After it had dried I applied dye using a foam brush to one piece of fabric and I used Setacolor paints on the other piece.

This is the dyed fabric. You can see the pattern of the stamp a bit, but not as much as I had hoped. However this is how the painted fabric looks like:

Much better, don't you think?