Adding to Helen's list, Alley Cat Allies is doing "Every Kitty, Every City" conferences around the country. Best Friends does regional conferences. Be sure to sign up as a Best Friends Network Partner to get on the email list for those along with monthly emails updating goings on in your area, opportunity for grants, ResQwalk and Strut Your Mutt. Also, Best Friends and HSUS representatives in or near your area will come to you...they offer expert speakers on a variety of topics. I don't think there is any fee for that and it can be very impactful if you invite public officials. Don't forget Maddie's University -- scads of self-paced learning on any topic you can imagine.
A good resource for listings & reminders is the ASPCAPro calendar (published quarterly). It also lists webinars, major & minor holidays & awareness like "Nation Mutt Day", "National Dog Biscuit Day", "National Pet Poison Prevention Week" etc. and lists suggestions for promotions or events to coordinate with the themes.