I run a small non- profit rescue. And for a whole lot of community things, you must be a 501(c)(3) organization. (We're in process, and it is a $400.00 and many hour pain in the ass with the IRS).
We have online auctions and raffles. Be careful with raffles- unless you have the right status, they can be illegal.
You can also use an artfire kiosk to sell things. For larger fundraisers (surgeries, big influxes of new dogs, etc.) I often raffle off a quilt, and have other folks donate things to auction. I use the forums that I AM ALREADY a part of, and Facebook, as well as e-mailings to existing supporters to get out the word.
There are so many illegitimate rescues out there that most local event will require that you are at the very least a registered non-profit corporation. (In most states, this is easily done for a nominal fee.) And don't get frustrated when you are asked over and over for credentials. Remember, they are trying to protect both the animals and donater's from scammers, and the scams are all over the place.