I haven't made the switch to washable pads just because I'm afraid they will get confused. Last week I had my yoga mat left out ( I usually roll it up and put it away), and McKenzie used it like a potty pad, so I'm thinking that if I got anything fabric like, she would think it was acceptable to potty on blankies, ect.
I know some have had good successes using them but I think we are going to stick with our disposable ones. pee-pads.com has good ones that are the most affordable I've seen and never leak
Someone also recommended pishpads.com for their reusable pads. They are pricey, but are also machine washable and reusable and they don't appear to look like fabric