After a couple of weeks with a change from a local number to a toll free my results-
The overall conversion rates stayed the same, but I did get a couple of telephone orders from people who may not have ordered otherwise. They said they had seen my site online, and didn't have a chance to order right then, but wrote down the phone number. If it had remained the local number, I don't think they would have bothered. Although I didn't ask them that, next time I will. If I had been in their position, I would be much more likely to write down a toll free than a local number.