If you are going to wash more than 2 yards of fabric, it gets less twisted and wrinkled if you wash it folded-accordian style. I lay mine out on the bed (opening up the original fold from the bolt) and fan-fold or accordian-pleat in about 12" sections. I don't measure or anything, just do it as easily as I can. Then, I use big safety pins and pin the selvedge edges on each side - 2 or 3 pins, depending on how wide it ends up. It goes into the washer and dryer like this, and comes out nicely- not all twisted up.
I had heard about this, then saw this tip in Quilter's Newsletter Magazine. I tried it after than, and found it very helpful, so I'm passing it along.