How do you start an Horse Rescue in Ontario and who should I contact to get istance with the paperwork?

My fiance and I are trying to start an Equine rescue. We have a website to promote our facility already but I don't know much about the legalities or paperwork to get "officially" off the ground which we are hoping to do in the Spring of 2012. I have 22 years of experience with horses and am eager to get started. Our website has already generated an enormous amount of positive feedback. But some people are asking about tax reciepts? We want to be a not-for-profit organization, however we don't know who we should talk to so that these generous donators can be given proper reciepts etc. Please help!!! No negative comments please!